Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “OPSONINS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,081 records · Page 60Linked to original sources
PubMed1994

[Analysis of complement-mediated phagocytosis in systemic lupus erythematosus model mice, NZB/W F1].

We have attempted to examine the cause of lowering phagocytic activity of phagocytes on clearance of bacteria in SLE patients. The experiments were performed in SLE model mice, NZB/WF1 female mice (BWF1). The ratio of the cells which phagocytized fluorescent microspheres and possessed Mac-1 on both peripheral blood leukocytes (PBL) and peritoneal macrophages (PMo) in BWF1 female mice was shown decreasing by using the flow cytometric method before the present of typical symptoms of SLE (under 25 weeks-old), i.e., the appearance of ANA and IgG deposits in glomeruli. In a period of showing the symptoms of SLE (over 25 weeks-old), the ratio of Mac-1 positive cells on PBL increased, but phagocytic function of these cells did not increase. On the other hand, on PMo, they decreased together in that period. Moreover, the phagocytosis of PMo in 15, 25, 35 weeks-old mice against fluorescent microspheres showed a significant increase (1.7 times) by replacing opsonin with normal (ddY) murine serum instead of BWF1 murine serum, and the phagocytosis of PMo treated with anti-Mac-1 antibody (M1/70) showed a significant inhibition (46%) against that of untreated PMo. These results indicate that lowering phagocytic activity of phagocytes on primary defence against microbial infections in SLE patients is due possibly to decrease of C3 activity in the serum rather than a decrease of positive percentage and function of Mac-1 on these cells.

Animals↗
PubMed2005

Interaction with blood components plays a crucial role in asialoglycoprotein receptor-mediated in vivo gene transfer by galactosylated lipoplex.

In this study, we evaluated the effect of blood components (whole blood and serum) on asialoglycoprotein receptor-mediated in vivo gene transfer. The hepatic transfection activity of galactosylated lipoplex preincubated with serum was approximately 10 times higher than that without incubation after intraportal injection in mice. However, preincubation with whole blood significantly reduced hepatic transfection activity. Fluorescent resonance energy transfer analysis and agarose gel electrophoresis revealed that preincubation with serum reduced the degree of destabilization of the galactosylated lipoplex in blood, partially supporting enhanced hepatic transfection activity by preincubation with serum. Inhibition of hepatic transfection activity by predosing galactosylated bovine serum albumin indicated that the galactosylated lipoplex exposed to serum is recognized by asialoglycoprotein-receptors on hepatocytes. Inactivation of serum prior to mixing with galactosylated lipoplex reduced liver accumulation and completely abolished enhancement of hepatic transfection activity by preincubation with active serum, suggesting that not only the stability of the lipoplex in blood but also the serum opsonin activity plays important roles. Alternatively, preincubation with inactivated serum reduced the lung accumulation and inflammatory cytokine production of galactosylated lipoplex. The information provided by this study will be valuable for the future use, design, and development of galactosylated lipoplex for in vivo asialoglycoprotein receptor-mediated gene transfer.

Animals↗
PubMed1994

Therapeutic efficacy of monoclonal antibodies to Cryptococcus neoformans glucuronoxylomannan alone and in combination with amphotericin B.

The therapeutic efficacy of the immunoglobulin G1 (IgG1) monoclonal antibody (MAb) 2H1 to the Cryptococcus neoformans capsular polysaccharide was studied with and without amphotericin B (AmB) in a murine model of intravenous (i.v.) infection. MAb and AmB were administered by intraperitoneal (i.p.) injection after i.v. infection with a C. neoformans serotype D strain. Intraperitoneal administration of MAb 2H1 resulted in rapid distribution to the intravascular compartment, and the half-lives of i.p. and i.v. administered MAb were similar. Administration of MAb 2H1 alone resulted in increased survival, decreased lung fungal burden, and reduced serum glucuronoxylomannan antigen levels when given 2 to 6 h but not 24 h after infection. In vivo, the combination of MAb 2H1 and AmB was more effective at prolonging survival than either agent alone. MAbs of IgM, IgG1, IgG3, and IgA isotypes given 1 day after infection were effective in reducing serum GXM-D levels, with their relative efficacy being IgG1 > IgG3 > IgM > IgA. In vitro, MAb 2H1 was a potent opsonin of C. neoformans and the combination of MAb 2H1 and AmB was more effective than either agent alone in decreasing C. neoformans colony counts in the presence of the murine macrophage cell line J774.16. The results confirm that capsule-binding MAbs can enhance the effect of AmB against C. neoformans and provide support for considering combined therapy in humans.

Amphotericin B↗
PubMed1999

Amphotericin B and fluconazole affect cellular charge, macrophage phagocytosis, and cellular morphology of Cryptococcus neoformans at subinhibitory concentrations.

Amphotericin B (AmB) and fluconazole (FLU) are the major antifungal drugs used in the treatment of cryptococcosis. Both drugs are believed to exert their antifungal effects through actions on cell membrane sterols. In this study we investigated whether AmB and FLU had other, more subtle effects on C. neoformans that could contribute to their therapeutic efficacy. C. neoformans cells were grown in media with subinhibitory concentrations of either AmB or FLU and analyzed for cellular charge, phagocytosis by macrophages with antibody and complement opsonins, appearance by scanning electron and light microscopies, and release of the capsular polysaccharide glucuronoxylomannan into the culture medium. Growth in the presence of either AmB or FLU resulted in major reductions in cellular charge, as measured by determination of the zeta potential. Phagocytosis studies demonstrated that exposure of C. neoformans to subinhibitory concentrations of AmB or FLU enhanced phagocytosis by macrophages. Scanning electron microscopy revealed that a large proportion of cells had an altered capsular appearance. Cells grown in medium with either AmB or FLU were smaller and released more glucuronoxylomannan into the culture medium than cells grown without antibiotics. The results suggest additional mechanisms of action for AmB and FLU that may be operative in body compartments where drug levels do not achieve the MICs. Furthermore, the results suggest mechanisms by which AmB and FLU can cooperate with humoral and cellular immune defense systems in controlling C. neoformans infections.

Amphotericin B↗
PubMed2001

Are the opsonophagocytic activities of antibodies in infant sera measured by different pneumococcal phagocytosis assays comparable?

Host protection against Streptococcus pneumoniae is mainly mediated by opsonin-dependent phagocytosis. Several techniques for measuring opsonophagocytic activity (OPA) of antibodies to S. pneumoniae have been standardized and used. These include the viable cell-assay, flow-cytometric assays, and an assay utilizing radiolabeled bacteria. Using these different methods, we measured the OPA of antibodies to S. pneumoniae types 6B and 19F from the sera of infants immunized with a pneumococcal conjugate vaccine, PncCRM. Generally, the results obtained by the various techniques correlated well, although serotype-specific differences were found (6B, r = 0.78 to 0.95, P < 0.001; 19F, r = 0.50 to 0.84, P < 0.001). The same serotype-specific differences were observed for the relationship between the concentrations of specific immunoglobulin G antibodies measured by enzyme immunoassay and the OPA. Since the sensitivities of the OPA assays differed, the most prominent discrepancies between the techniques were found at low antibody concentrations.

Antibodies, Viral↗
PubMed1998

Serologic response to cell wall mannoproteins and proteins of Candida albicans.

The cell wall of Candida albicans not only is the structure in which many biological functions essential for the fungal cells reside but also is a significant source of candidal antigens. The major cell wall components that elicit a response from the host immune system are proteins and glycoproteins, the latter being predominantly mannoproteins. Both the carbohydrate and protein moieties are able to trigger immune responses. Although cell-mediated immunity is often considered to be the most important line of defense against candidiasis, cell wall protein and glycoprotein components also elicit a potent humoral response from the host that may include some protective antibodies. Proteins and glycoproteins exposed at the most external layers of the wall structure are involved in several types of interactions of fungal cells with the exocellular environment. Thus, coating of fungal cells with host antibodies has the potential to influence profoundly the host-parasite interaction by affecting antibody-mediated functions such as opsonin-enhanced phagocytosis and blocking the binding activity of fungal adhesins for host ligands. In this review, the various members of the protein and glycoprotein fraction of the C. albicans cell wall that elicit an antibody response in vivo are examined. Although a number of proteins have been shown to stimulate an antibody response, for some of these species the response is not universal. On the other hand, some of the studies demonstrate that certain cell wall antigens and anti-cell wall antibodies may be the basis for developing specific and sensitive serologic tests for the diagnosis of candidasis, particularly the disseminated form. In addition, recent studies have focused on the potential for antibodies to cell wall protein determinants to protect the host against infection. Hence, a better understanding of the humoral response to cell wall antigens of C. albicans may provide the basis for the development of (i) effective procedures for the serodiagnosis of disseminated candidiasis and (ii) novel prophylactic (vaccination) and therapeutic strategies for the management of this type of infection.

Animals↗
PubMed2006

Characterization of the receptor-ligand pathways important for entry and survival of Francisella tularensis in human macrophages.

Inhalational pneumonic tularemia, caused by Francisella tularensis, is lethal in humans. F. tularensis is phagocytosed by macrophages followed by escape from phagosomes into the cytoplasm. Little is known of the phagocytic mechanisms for Francisella, particularly as they relate to the lung and alveolar macrophages. Here we examined receptors on primary human monocytes and macrophages which mediate the phagocytosis and intracellular survival of F. novicida. F. novicida association with monocyte-derived macrophages (MDM) was greater than with monocytes. Bacteria were readily ingested, as shown by electron microscopy. Bacterial association was significantly increased in fresh serum and only partially decreased in heat-inactivated serum. A role for both complement receptor 3 (CR3) and Fcgamma receptors in uptake was supported by studies using a CR3-expressing cell line and by down-modulation of Fcgamma receptors on MDM, respectively. Consistent with Fcgamma receptor involvement, antibody in nonimmune human serum was detected on the surface of Francisella. In the absence of serum opsonins, competitive inhibition of mannose receptor (MR) activity on MDM with mannan decreased the association of F. novicida and opsonization of F. novicida with lung collectin surfactant protein A (SP-A) increased bacterial association and intracellular survival. This study demonstrates that human macrophages phagocytose more Francisella than monocytes with contributions from CR3, Fcgamma receptors, the MR, and SP-A present in lung alveoli.

Antibodies, Bacterial↗
PubMed2006

Biological Trojan horse: Antigen 43 provides specific bacterial uptake and survival in human neutrophils.

Escherichia coli is a versatile pathogen causing millions of infections in humans every year. This bacterium can form multicellular aggregates when it expresses a self-associating protein, antigen 43 (Ag43), on its surface. We have discovered that Ag43-expressing E. coli cells are efficiently taken up by human defense cells, polymorphonuclear neutrophils (PMNs), in an opsonin-independent manner. Surprisingly, the phagocytosed bacteria were not immediately killed but resided as tight aggregates within the PMNs. Our observations indicate that Ag43-mediated uptake and survival in PMNs constitute a mechanism to subvert one of the primary defense mechanisms of the human body.

Adhesins, Bacterial↗
PubMed1974

Bovine venereal vibriosis: variations in immunoglobulin class of antibodies in genital secretions and serum.

The immunoglobulin classes of antibodies to Campylobacter (Vibrio) fetus in cervicovaginal mucus (CVM) were determined by the indirect fluorescent antibody test at sequential periods, since the order of class appearance has not been established for specific secretory immune responses. In the local immune response to C. fetus immunoglobulin M (IgM) antibodies appeared first, immunoglobulin A (IgA) antibodies next, and immunoglobulin G (IgG) last. IgM antibodies were quite transient, but IgG antibodies remained longer, and those of the IgA class persisted until the end of the experimental period (up to 10 months). Since differences appear to exist between immune mechanisms at cervicovaginal and uterine sites, as well as between immune responses induced by local and systemic immunizations, the immunoglobulin classes of antibodies in uterine secretions were compared with the classes in CVM and serum. Uterine antibodies arose coincidently with uterine lesions in heifers slaughtered after short periods of infection. In convalescent animals only IgA antibodies were found in CVM, whereas the predominant class of antibodies in the uterine secretions was IgG(1) in three of four animals studied. Only IgG antibodies were detected in CVM and uterine secretions of systemically immunized animals. These findings could account for faster clearance of C. fetus from the uterus than from the cervicovaginal area in locally infected animals and for failure of colonization in systemically immunized animals, because IgG antibodies are good opsonins and IgA antibodies are not. IgA antibodies do immobilize C. fetus, however, so they could prevent recolonization of the uterus in cervicovaginal carriers.

Journal Article↗
PubMed1976

Complement system in pneumococcal infections.

The properdin or alternate complement pathway may function as a heat-labile opsonin for pneumococci, and evidence has been sought for its activation in pneumococcal infections. Twenty-two patients had determinations of C1q, C4, properdin factor B, C3, and hemolytic complement during hospitalization for pneumococcal infection. Measurements were made during the first 36 h after admission on 16 patients and later during recovery on 16. The admission and recovery values were compared statistically with each other and with the levels of 15 normal individuals. The admission and recovery mean values were normal and nearly identical for C1q and C4, which are two early components of the classical pathway. The mean level of factor N, a properdin pathway component, was significantly depressed on admission, but the mean recovery value was normal. Admission levels for C3, a component of the late common pathway, were depressed, and recovery values were normal. Total hemolytic complement was decreased on admission, although the decrease was not significant for the patients with both admission and recovery determinations. The findings are consistent with the hypothesis that factor B is turned over rapidly, or consumed, early in pneumococcal infections; alternatively, persons with low baseline factor B levels may be particularly susceptible to pneumococcal infection.

Adult↗
PubMed1976

Inhibition of phagocytosis by cryptococcal polysaccharide: dissociation of the attachment and ingestion phases of phagocytosis.

The effects of cryptococcal polysaccharide and selected serum factors on (i) the attachment of Cryptococcus neoformans to macrophages and (ii) the subsequent ingestion of yeast cells by the macrophages were investigated. Percent attachment was measured after incubation of yeast cells with macrophages at 4 C. Percent engulfment was determined after incubation of yeast cells and macrophages at 37 C. Nonencapsulated yeast cells readily attached to macrophages at the low temperature and were engulfed at a high rate at 37 C, whereas encapsulated yeast cells attached to macrophages at low rates and were engulfed at low rates. Addition of varying doses of purified cryptococcal polysaccharide to nonencapsulated yeast cells inhibited attachment at approximately the same concentration of polysaccharide required for inhibition of engulfment. Nonencapsulated yeast cells that attached to macrophages at 4 C were eluted from the macrophages by addition of purified cryptococcal polysaccharide to the incubation medium. Heat-labile opsonins were not required for attachment of yeast cells to macrophages, but they were necessary for maximal initial rates of phagocytosis. Heat-stable components of serum facilitated attachment of cryptococci, but their most important function appeared to be triggering the ingestion of attached yeast. Specific antiserum had no effect on the attachment and engulfment of nonencapsulated cryptococci, and the antiserum produced only a small enhancement of the engulfment of encapsulated cryptococci.

Animals↗
PubMed1976

Humoral immunity to Streptococcus pneumoniae induced by a pneumococcal ribosomal protein fraction.

Isolation of a protective subfraction of ribosomes from Streptococcus pneumoniae has been achieved, and the immune response it induces has been investigated. Mice immunized with pneumococcal ribosomes or purified protein extracted from the ribosomal preparation (2-CE protein) exhibit similar survival rates upon challenge by virulent S. pneumoniae. In contrast, recipients of purified ribosomal ribonucleic acid were never protected against pneumococcal challenge. Serum from mice immunized with pneumococcal ribosomes or 2-CE protein passively immunized syngeneic recipients against pneumococcal challenge, whereas spleen cells from the same donors were unable to transfer immunity. Passive immunization with antiribosome serum could be abrogated by absorption with whole ribosomes, 2-CE protein, or various serotypes of S. pneumoniae (capsular types 2, 3, 6, and 14). Antiribosome serum significantly enhanced clearance of S. pneumoniae from mouse blood in vivo and in vitro. This required phagocytic cells, since antiribosome serum alone, with or without complement, supported growth of S. pneumoniae to an extent comparable to normal serum. The data suggest that the primary immunogen of pneumococcal ribosomes resides in the protein fraction. Further, the immunity induced by the protein fraction is mediated by antibody that appears to function as an opsonin for S. pneumoniae.

Animals↗
PubMed1980

Kinetics of interaction and fate of Pasteurella hemolytica in bovine alveolar macrophages.

To study the role of pulmonary alveolar macrophages (PAMs) in phagocytizing Pasteurella hemolytica, we developed an in vitro cultivation method for preparing them. This procedure provided an adherent monolayer of PAMs which were nonspecific esterase-positive and phagocytized latex beads. The phagocytosis and fate of P. hemolytica (biotype A, serotype 1) by PAMs in suspension were studied. The kinetics of phagocytosis were determined by quantitatively measuring the uptake of 24-h [(3)H]thymidine-labeled bacteria by the PAMs in the presence of opsonins. Results showed that the uptake of P. hemolytica was enhanced in the presence of normal serum or antiserum. A total of 90% of the bacteria were phagocytized in the presence of normal adult bovine serum, and up to 95% were phagocytized in the presence of an antiserum. These studies also showed that normal serum, but not fetal calf serum, contained heat-stable natural antibodies which readily initiated the opsonization of P. hemolytica. The heat-labile complement system was also involved in the opsonization. The fate of P. hemolytica inside the PAMs was investigated by transmission electron microscopy and by the viable plate count method. Approximately 90% of the normal serum- or antiserum-opsonized P. hemolytica were phagocytized by PAMs at a bacteria/PAM ratio of 20:1 and were completely degraded after 60 min of exposure. Prolonged incubation of this mixture of bacteria and PAMs resulted in cytotoxic changes and destruction of PAMs. At a low bacteria/PAM ratio (10:1 or less), there was phagocytosis and killing of bacteria but no cytotoxic changes on the PAMs. The exact mechanism which initiated this phenomenon was not demonstrated. Perhaps toxic substance(s) released by the excess unphagocytized bacteria caused the cytotoxic changes to the PAMs.

Animals↗
PubMed1982

Differences in phagocytosis and killing by alveolar macrophages from humans, rabbits, rats, and hamsters.

Phagocytosis and killing by alveolar macrophages from humans, rabbits, rats, and hamsters, were compared in vitro. In the absence of serum opsonins, human alveolar macrophages could phagocytize Staphylococcus aureus Cowan I (protein A positive), but not S. aureus EMS (protein A negative) or Pseudomonas aeruginosa MN. In contrast, rabbit, rat, and hamster alveolar macrophages did not phagocytize S. aureus Cowan I or other nonopsonized bacteria. Human alveolar macrophages, but not other species, stained positively with fluorescein isothiocyanate-conjugated protein A. When opsonized bacterial were studied, phagocytosis by human, rabbit, and hamster alveolar macrophages was found to be mediated by both Fc and C3 receptors. However, only Fc receptor-mediated phagocytosis of bacteria was demonstrated for rat alveolar macrophages. Differences were also found in the kinetics of bacterial killing by alveolar macrophages from different species. Human and rabbit alveolar macrophages rapidly killed opsonized S. aureus Cowan I. However, bacterial killing by hamster alveolar macrophages proceeded at a slower rate, and rat alveolar macrophages completely failed to kill S. aureus. These significant differences in the function of alveolar macrophages from four different species emphasize the need to document the appropriateness of animal models before using them to predict the biological activities of human alveolar macrophages.

Animals↗
PubMed1983

Fate of Pasteurella hemolytica in conventionally raised and germfree mice.

When Pasteurella hemolytica was introduced into conventionally raised ICR mice by a variety of routes (intraperitoneal, aerogenic, and oral), the inoculum was rapidly eliminated, and none of the mice died. Even when the inoculum was injected intraperitoneally into sublethally irradiated (600 rads) mice, the organisms were eliminated rapidly unless suspended in 10% hog gastric mucin. When germfree ICR mice were orally infected with P. hemolytica, the infection established itself in the intestinal tract and spread to the mesenteric lymph nodes but did not progress beyond this point. Despite the inability of P. hemolytica to establish itself systemically, the organism multiplied freely in mouse blood and a homogenate of normal mouse lung in vitro. Normal mouse peritoneal macrophages could phagocytose P. hemolytica in vitro, although not as efficiently as the control Listeria monocytogenes suspensions. The addition of hyperimmune bovine serum (opsonin) to the P. hemolytica suspension increased phagocytosis but did not greatly affect the subsequent bactericidal activity of the macrophages in vitro. The reason for the lack of pathogenicity shown by P. hemolytica in normal mice remains enigmatic.

Animals↗
PubMed1983

Localization of complement component 3 on Streptococcus pneumoniae: anti-capsular antibody causes complement deposition on the pneumococcal capsule.

We have previously shown that complement component 3 (C3) deposited onto encapsulated Streptococcus pneumoniae by anti-capsular antibody (Ab) is a more efficient opsonin in vitro and in vivo than C3 deposited by anti-cell wall Ab (Brown et al., J. Clin. Invest. 69:85-98, 1982). In the present study, we explored the cellular location of C3b molecules that differ in opsonic efficiency by using avidin-ferritin to localize biotinylated Ab and C3 molecules on S. pneumoniae for electron microscopy. Anti-cell wall Ab and C3b molecules deposited by this Ab on unencapsulated S. pneumoniae were localized to S. pneumoniae cell walls. Anti-capsular Ab and C3b deposited by this Ab were seen in clusters on encapsulated S. pneumoniae at a distance from the cell wall. However, no avidin-ferritin staining of encapsulated S. pneumoniae was seen on incubation with biotinyl-anti-cell wall Ab, biotinylated C3 fixed by anti-cell wall Ab, or nonimmune serum containing biotinyl-C3. In each case, uptake of the biotinylated component was proven by radioactivity measurements, since biotinylated Ab and C3 were also radiolabeled with 125I. When avidin-ferritin did not bind to biotinylated components. Ouchterlony analysis indicated that C3 was bound to cell wall components on the encapsulated organisms. Thus, we conclude that, for encapsulated S. pneumoniae, opsonically efficient C3b molecules, deposited by anti-capsular Ab, are located on the S. pneumoniae capsule, whereas the opsonically inefficient C3b molecules deposited by anti-cell wall Ab or nonimmune serum are located on the cell wall. A major reason for the increased virulence of encapsulated compared to unencapsulated S. pneumoniae is that, in the absence of anti-capsular Ab, the S. pneumoniae capsule interferes with the recognition of cell wall-bound C3b molecules by phagocytic cell receptors.

Antibodies, Bacterial↗
PubMed1985

Opsonized streptococcal cell walls cross-link human leukocytes and erythrocytes by complement receptors.

Serum-opsonized group A streptococcal cell walls, consisting of peptidoglycan-polysaccharide polymers (PG-APS), induced monolayers of human neutrophils, monocytes, and eosinophils to aggregate. When erythrocytes were present in the incubation medium, they also were associated with the leukocyte aggregates. By immunofluorescence staining, PG-APS was localized at the site of cell-to-cell contact. By scanning electron microscopy the cells appeared to adhere to one another by surface contact; filopodia often acted as connectors, particularly in leukocyte-erythrocyte interaction. Cellular binding of PG-APS and aggregation were dependent upon C3 fixation. No aggregation was observed when heat-inactivated serum was used as an opsonin. In contrast to peptidoglycan, an activator of the alternative complement pathway, the group-specific polysaccharide moiety of PG-APS induced no cellular aggregation. Rosette formation was observed in suspensions when neutrophils were incubated with erythrocytes coated with C3b-opsonized PG-APS. Cell monolayers bound serum-opsonized PG-APS, but aggregation was observed only when serum was present in the incubation medium. Similar results were obtained with C5-deficient serum. No aggregation was observed with heat-inactivated serum or bovine serum albumin. A heat-labile serum component(s) appears to be required to elicit leukocyte aggregation. It is suggested that C3 fixed to PG-APS acts as a bridge to link cells together in clusters as a result of common recognition of C3 by leukocyte and erythrocyte complement receptors.

Animals↗
PubMed1985

Opsonic requirements for phagocytosis of Legionella micdadei by polymorphonuclear leukocytes.

The roles of the classical and alternative pathways of complement activation and of antibody in the phagocytosis of Legionella micdadei by polymorphonuclear leukocytes were studied. Normal serum was treated with the appropriate chelators or with heat to inactivate the classical, alternate, or both pathways of complement activation. Normal and complement-depleted sera with or without antibody were employed as opsonins for L. micdadei in phagocytosis assays. There was no difference in the phagocytosis of L. micdadei promoted by normal serum and either C4-deficient serum or serum in which the classical pathway had been inactivated. Both normal and classical pathway-deficient sera promoted significantly greater phagocytosis than did sera in which the alternate pathway or both the alternate and classical pathways had been inactivated. Thus, polymorphonuclear leukocyte phagocytosis of L. micdadei in the absence of antibody required an intact alternate pathway. Specific antibody partially restored opsonization to sera deficient in the alternate or both complement pathways, but phagocytosis was still significantly less than that with the alternate pathway intact.

Antibodies↗