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PubMed1987

Association of colorectal tumor epithelium expressing HLA-D/DR with CD8-positive T-cells and mononuclear phagocytes.

Forty-eight human colorectal adenocarcinomas, removed at different stages of development, have been examined immunohistochemically for the expression of class II molecules and for the relationship of such class II expression to infiltrating leukocytes. Forty-four% of tumor epithelium samples express class II molecules. This expression is confined to the proteins coded for by the HLA-D/DR subregion although the surrounding infiltrating cells express HLA-D/DR, -DQ, and -DP coded proteins. In addition, there are significantly greater numbers of mononuclear phagocytes and T-cells of the CD8 antibody-positive subset associated with the tumors expressing class II molecules on tumor epithelium compared to the class II-negative tumors. The T-cells appear not to be activated judging by the lack of expression of the receptor for interleukin-2 but the mononuclear phagocytes express CR1, the receptor for the complement component C3b, which suggests that they are stimulated.

Antibodies, Monoclonal↗
PubMed1988

C3d,g is present in normal human epidermal basement membrane.

mAb as well as polyclonal anti-human C3d antibodies were found to specifically bind to the epidermal basement membrane zone of normal human adult and neonatal skin in a linear continuous pattern on direct immunofluorescence microscopy. No such binding was found in dermal microvascular basement membranes. Studies of normal adult human skin using a rat mAb specific for C3g revealed the same pattern of epidermal basement membrane staining. Control polyclonal antibodies directed against C3, C3c, C5, IgG, IgA, or IgM showed no evidence of epidermal basement membrane binding or in situ deposits of immune complexes in samples of normal human skin that were all positive for C3d and C3g. Pre-adsorption of monoclonal or polyclonal anti-human C3d with purified human C3d completely blocked these reagents' epidermal basement membrane reactivity. Anti-human C3d epidermal basement membrane binding was not diminished by pre-treatment of substrate with antibodies directed against C3, C3c, C5, laminin, fibronectin, or type IV collagen as well as bullous pemphigoid, KF-1, or epidermolysis bullosa acquisita Ag. Direct immunofluorescence microscopy studies on 1 M NaCl split human skin showed that C3d and C3g were found in the base of the cleavage plane created within the lamina lucida. By immunoelectron microscopy, C3d was found along the base of the lamina densa and in the sublamina densa region of normal human epidermal basement membrane. Although anti-human C3d epidermal basement membrane binding was not altered by treatment of 6 micron skin sections with buffers of varying pH and ionic concentration, binding was abolished by treating dermal portions of salt split skin with 0.1 M dithiothreitol in 8 M urea. Studies of a patient with congenital C3 deficiency revealed that there was no binding of anti-human C3d or anti-human C3g to this subject's epidermal basement membrane. Moreover, treatment of this patient's skin with aged human serum containing C3d,g or purified human C3 did not restore epidermal basement membrane anti-human C3d binding. These studies demonstrate that C3d,g or a closely related C3 fragment is present in the epidermal basement membrane zone of normal human skin.

Adult↗
PubMed1988

[Preventive long-term intravenous immunoglobulin infusion in children with acute lymphatic leukemia. I. Anticomplementary activity of gamma globulin preparations is a function of the preparation and IgG concentration prior to infusions].

The influence of intravenous gammaglobulin infusions (ivGG) on hemolytic complement function and the concentration of serum C3 and its split product C3dg was studied in 20 children with acute lymphocytic leukemia (ALL) undergoing ivGG prophylaxis. IvGG was infused once monthly over a period of 20 months using two different preparations commercially available. Serum and EDTA-plasma were collected before initiation of ivGG therapy (time 1), after 10 and 20 months (time 2 and 3), before and immediately after the infusions. IvGG was infused in connection with chemotherapy (according to the CoAll 82 protocol). 16 of 60 sera collected prior to infusions contained less than 700 mg/dl IgG. Mean IgG concentrations could be raised to 198 mg/dl (time 1), 219 mg/dl (time 2), and 213 mg/dl (time 3), respectively. -CH 50 prior to infusions was below normal in 15 of 59 sera, afterwards in 25 of 59 sera. AP 50 before (after) infusions was decreased in 29 of 59 (36 of 60) sera, C3 in 18 of 60 (24 of 60) sera. C3dg was slightly elevated in one EDTA-plasma prior to ivGG infusions and in 5 of the plasmas following infusions. IvGG infusions resulted in a significant loss of hemolytic activity of serum complement (p less than 0.01, F-test). The effect was more profound if IgG concentrations before infusions were less than 700 mg/dl, but this was true for only one of the two used ivGG preparations. The long term follow up over two years showed no significant changes of complement functions (F-test), indicating complete recovery of complement function from short term anticomplementary effects.

Child↗
PubMed1987

Structural alterations of marrow during inflammation.

In response to infections and inflammations, bone marrow reacts to mobilize its granulocyte reserve. Three sets of factors are involved in this mobilization. The structure of the sinus wall is altered and adventitial cells retract to permit interaction of migrating cells with the endothelium. During the maturation process, granulocytes lose their binding potential to the supporting stroma, but their motility, chemotactic ability, and deformability increase. Consequently, they move toward the sinus endothelium with which they interact to enter the circulation. Soluble factors are also involved in granulocyte mobilization. The best characterized of these factors is C3e, an acidic fragment of the alpha chain of C3 with MW of 10-12 KD and ability to bind to granulocyte membrane. Other soluble factors may also be involved, but due to lack of adequate methodology, this area has been relatively underexplored.

Animals↗
PubMed1986

An efficient one-step method for isolating immune complexes from whole serum using a monoclonal anti-C3g affinity immunosorbent.

A simple and efficient method of extracting complement-fixing immune complexes (IC) from whole serum and recovering them has been developed. 125I-labelled, in vitro prepared IC in whole serum were incubated with Sepharose 4B covalently linked to monoclonal anti-C3g or anti-C1q and the binding and recovery of IC was monitored by radioactivity. The anti-C3g immunosorbent bound 45% and 76% of HAGG and BSA-anti-BSA IC respectively, all of which were recovered by elution with 4M MgCl2. The anti-C1q immunosorbent only bound 14% and 12% of the same IC and only 64% were recovered by eluting with 4M MgCl2. The IC extracted by the anti-C3g immunosorbent included those capable of extraction by the anti-C1q. The anti-C3g monoclonal recognizes not only the iC3b fragment of C3 and will therefore bind IC with affinity for bovine conglutinin but also subsequent degradation products containing the C3g antigen. Its wide range of reactivity for IC plus its excellent recovery properties make it the immunosorbent of choice for isolating complement-fixing IC.

Antibodies, Monoclonal↗
PubMed1986

Evaluation of C3b/C3bi opsonization and chemiluminescence with selected yeasts and bacteria using sera of different opsonic potential.

C3 fragment opsonization and chemiluminescence were assessed using two yeasts (Saccharomyces cerevisiae and Candida albicans) and two strains of bacteria (Staphylococcus aureus and Escherichia coli) following incubation with sera previously shown to be either efficient or poor in the opsonization of baker's yeast. Sera with poor function consistently fixed lower levels of C3 fragments and generated less chemiluminescence with all four organisms than sera with normal function. The differences were most marked with the two yeasts. We conclude that sera with normal complement function but manifesting a relatively common defect in the opsonization of baker's yeast have a general opsonic defect.

Adult↗
PubMed1986

The role of opsonins in vacuolar sealing and the ingestion of zymosan by human neutrophils.

After opsonization with whole human serum, with IgG antibody alone or with C3 fragments alone, the ingestion of zymosan particles by human neutrophils was found to correlate most closely with the efficiency of C3 fragment deposition on the zymosan surface. Selective opsonization of zymosan particles with IgG did not promote phagocytosis at all in suspension, but could promote ingestion after particle-cell contact was induced by centrifugation. In contrast, zymosan particles in suspension selectively opsonized by C3 fragments were ingested as efficiently as those opsonized with whole serum, and we suggest that C3 fragments provide the principal stimulus for phagocytosis of zymosan. The process of vacuolar sealing was not dependent on the state of opsonization of the particles and was significantly more efficient with unopsonized particles, indicating that formation of unsealed vacuoles is not due to a failure of the 'zipper' mechanism of sequential interaction of cell surface receptors and opsonic ligands.

Adult↗
PubMed1985

Molecular associations of class II MHC antigens in mitogen-stimulated B cells.

Previously, we showed that murine B cell membrane proteins undergo rearrangements in the plasma membrane to form new molecular associations in response to mitogenic stimulation. These complexes were covalently stabilized by photoreactive cross-linking agents and were analyzed by SDS PAGE. We have now identified certain complexes that involve class II MHC products, the Ia antigens. Upon stimulation of B cells with LPS, Ia surface molecules (as identified by radioimmunoprecipitation with polyclonal anti-Ia antiserum) enter into a molecular complex with a 95-kd membrane-associated protein (p95) to form a 200-kd complex that may be stabilized by the cross-linking agent dithiobisphenylazide (DTPA). This molecular association is not observed upon stimulation with mitogenic anti-Ig reagents, nor with the polyclonal B cell activator 8-bromoguanosine. p95 is not a disulfide-linked molecule itself, and by separate immunoprecipitation experiments we have established that it is not a component of surface Ig, transferrin receptor, the B cell Fc receptor, or CR1, the receptor for complement component C3b. Further analysis of the association of Ia antigens with surface proteins, with the use of monoclonal antibodies directed against I-A or I-E, has demonstrated that each subregion gene product forms a unique molecular association. Precipitation of radiolabeled lysates from LPS-activated B cells with anti-I-A reveals the aforementioned association with p95. In contrast, the I-E antigen apparently forms complexes with a multimer of a 15-kd protein to give complexes of 45, 60, 75, and 90 kd. When analyzed by two-dimensional diagonal gels (nonreducing/reducing), only the I-E bands are revealed by autoradiography, indicating that the putative p15 that associates with I-E may not be accessible to surface labeling. The disparate molecular associations for I-A and I-E suggest that the formation of these distinct protein complexes may be functionally related to a different role in the process of cellular activation for each of these Ia subregion gene products.

Animals↗
PubMed1985

Suboptimal C3b/C3bi deposition and defective yeast opsonization. II. Partial purification and preliminary characterization of an opsonic co-factor able to correct sera with the defect.

Using a correction assay a factor essential for normal deposition of C3 fragments on zymosan was identified in fractions of serum obtained by Sephacryl S-300 gel filtration (eluting between IgG and albumin), preparative Pevikon block electrophoresis (eluting in the beta-region) and DEAE-ion-exchange chromatography (eluting immediately post IgG). Active material was also identified in a commercial preparation of transferrin. A combination of DEAE-ion-exchange chromatography and gel filtration was used to partially purify the co-factor. The factor has an approximate relative molecular mass of 70,000-80,000.

Chromatography, Gel↗