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At least 793 records · Page 44Linked to original sources
PubMed2001

Effect of deworming on human T cell responses to mycobacterial antigens in helminth-exposed individuals before and after bacille Calmette-Guérin (BCG) vaccination.

The protective efficacy of BCG vaccination against pulmonary tuberculosis (TB) is highly variable in different populations. The reason remains to be elucidated. This study aims to investigate the possible effect of intestinal helminths on the immune response to PPD in naturally immunized or BCG-vaccinated humans. The study population was assessed for helminthic infection and those found to be positive were randomly assigned to either an albendazole treatment group or a control group who received a placebo. The immune response to PPD was compared between the two groups. In addition, subjects who were tuberculin skin test-negative in both groups were BCG vaccinated and later on tested for PPD-specific responses. Albendazole induced elimination/or reduction in intestinal worms resulting in a significant improvement in T cell proliferation and in interferon-gamma production by peripheral blood mononuclear cells (PBMC) stimulated with PPD. Moreover, BCG vaccination significantly improved PPD-specific immune responses in the treated group but not in the placebo group. The differences in the in vivo skin test responses were not significant. The data show that cellular immune responses to PPD are reduced in persons with concurrent helminthic infections, perhaps reflecting a lowered resistance to mycobacterial infections. This could explain, at least in part, the reduced efficacy of BCG against TB in helminth-endemic areas of the world.

Adolescent↗
PubMed1996

Recall of original serologic response after challenge with homologous and heterologous Chlamydia trachomatis serovars.

Chlamydia trachomatis serovar-specific major outer membrane protein (MOMP) antigens are important targets of immune neutralization in vitro, and natural immunity to infection is associated with serovar specificity. Reinfection, often by different serovars, plays an essential role in chlamydial disease pathogenesis. By use of a murine model, the anamnestic serologic response was characterized following priming and challenge inoculations using 6 different serovars. The serologic response was evaluated using synthetic peptides representing MOMP variant segments (VS) 1,2,3, and 4 antigenic same serovar resulted in serologic responses to homologous VS1 peptides. After challenge with a different serovar, anti-VS1 serologic responses were often elicited with specificity to both the priming serovar and the challenge serovar. The recall of serologic response to the original serovar was typically dependent upon the antigenic relationship of the 2 serovars.

Amino Acid Sequence↗
PubMed1997

Recognition of the latency-associated immediate early protein IE63 of varicella-zoster virus by human memory T lymphocytes.

Varicella-zoster virus (VZV) is a human alpha herpesvirus that establishes latency in sensory ganglia. Latency is characterized by the abundant expression of the immediate early protein 63 (IE63), whereas other viral proteins have not yet been detected during the quiescent phase of VZV infection. The IE63 protein is a component of the virion and is expressed very early in the infectious cycle. The IE63 protein is also expressed in skin during episodes of varicella and herpes zoster. We have evaluated the cell-mediated immune response against IE63 in naturally immune adults with a history of chickenpox, by T lymphoproliferation and cytotoxicity assays. Among donors who had T cell proliferation to unfractionated VZV Ags from infected cell extract, 59% had T cell recognition of purified IE63. The CTL response to IE63 was equivalent to CTL recognition of IE62, the major tegument component of VZV whose immunogenicity has been previously described. IgG Abs against IE63 were detected in serum from healthy immune adults. These results indicate that IE63 is an important target of immunity to VZV. T cell recognition of IE63 is likely to be involved in controlling VZV reactivation from latency.

Adult↗
PubMed1991

[Immunologic reactivity in patients with disseminated pulmonary tuberculosis with polysensitization].

Study of immunologic reactivity in patients with disseminated pulmonary tuberculosis has demonstrated that 80% of patients have sensitization to Mycobacterium tuberculosis antigens, in addition to that to bacterial flora (Streptococcus, Staphylococcus, Pneumococcus). The degree of immunity system damage depends on the character of the course and dissemination of the pathologic process. Three degrees of immunity system damage were distinguished: sharply manifested degree with suppression of all types of cellular immune response and activation of humoral immunity, which is seen in patients with bilateral caseous pneumonia and military pulmonary tuberculosis; manifested degree with suppression of cellular immunity, natural organism's resistance and moderate decrease of humoral immunity typical of subacute disseminated pulmonary tuberculosis; moderate degree with mild changes in cellular and humoral immune response and natural organism's resistance and high sensitization in the lymphocyte blast transformation reaction with specific antigen, which occurs in chronic disseminated pulmonary tuberculosis.

Antigens, Bacterial↗
PubMed1994

Assessment of the humoral and cell-mediated immunity against the Plasmodium falciparum vaccine candidates circumsporozoite protein and SPf66 in adults living in highly endemic malarious areas of Papua New Guinea.

To assess natural immunity against the circumsporozoite (CS) protein and the synthetic vaccine SPf66, immunologic studies were carried out in a highly endemic malarious area of Papua New Guinea. Antibody prevalence, antibody titers, and T cell proliferation against both antigens were measured in 214 adults. Immunologic data were analyzed with respect to longitudinal malariologic and morbidity data. Evidence of genetic traits such as glucose-6-phosphate dehydrogenase deficiency and ovalocytosis was analyzed. Antibody prevalence was high, with 79% and 84% for CS protein and SPf66, respectively, while T cell proliferation was infrequent and low, with 14% and 12% responders, respectively. Anti-CS protein antibodies increased with age but showed no association to malaria indices or morbidity. No protective value was observed with T cell responses or with humoral response to SPf66. These results provide a first description of naturally developed immunity against SPf66 and suggest further studies in to fully understand the mechanism of immunity against this antigen.

Adolescent↗
PubMedDate not supplied

Natural and reinforced immunity against hapten-modified cells in vivo: importance of serum-borne and cellular factors.

Chromium 51-labelled murine splenocytes were injected intravenously into syngeneic non-immune recipients. The percentages of radioactivity recovered in the spleens and the livers were determined, together with the liver/spleen (L/S) radioactivity ratios. It was found that using trinitrobenzene sulphonate (TNBS)-treated cells resulted in a diminution of splenic recovery, with a concomitant augmentation of the L/S ratio, which corresponded to figures found when non-treated xenogeneic lymphocytes were injected. When using splenocytes modified with trifluoromethyl-dinitrobenzene sulphonate (CF3-DNBS)--an analogue of TNBS--this sort of natural immunity was not observed. As cell modifications with TNBS and CF3-DNBS have previously been shown to cross-react in purely cellular immunity tests, the striking difference observed here was tentatively attributed to differential sensitivity to serum-borne factors which mediate this in vivo natural resistance. These factors are likely to be naturally occurring anti-trinitrophenyl antibodies. Contrastingly, if TNBS- and CF3-DNBS-modified splenocytes were injected into either anti-TNBS or anti-CF3-DNBS immunized mice, the modification of radioactivity recovery and L/S indexes (compared to those in non-immunized controls) was always greater in the case of the CF3-DNBS cells. It is concluded that, of these two cross-reacting cell surface modifying treatments, one (TNBS) is sensitive both to natural and reinforced immunity, whereas the second (CF3-DNBS) is sensitive only to reinforced immunity. As we have previously shown in vitro, that CF3-DNBS-modified cells do not seem to be sensitive to cytotoxic antibodies, we believe that the in vivo immune rejection observed is essentially a cell-mediated reaction, whereas the natural immunity is mainly a serum-dependent reaction.

Animals↗
PubMed1990

Development of immunity to ocular chlamydial infection.

The development of "natural immunity" to homologous and heterologous ocular challenge with Chlamydia trachomatis was examined in cynomolgus monkeys given primary or secondary inoculations of C. trachomatis serovars B, C, and E. Overall, serovar E gave more severe disease than the other serovars. The amount of disease induced by the 2 serovar B strains examined, TW-5 and HAR-36, varied. In general, animals showed resistance to homologous secondary challenge, which was better characterized by a reduction in the recovery of culturable organisms than by a reduction in clinical disease. However, following initial heterologous challenge, neither resistance nor aggravation of disease was seen. These observations suggest that a trachoma vaccine will have to contain the serovar-specific antigenic determinants for multiple chlamydial serovars.

Animals↗
PubMed1994

[Alzheimer's disease and the immune system response].

Elements that belong to the natural immune system have been identified immunohistochemically in brain of patients with Alzheimer's disease (AD). Senile plaques and ghost tangles appear to be the site of chronic inflammatory response where reactive microglia, the brain resident macrophages, play a major role. Activation of the complement, coagulation and fibrinolysis systems also occur in such lesions. Nevertheless, the accumulation of plaques and tangles in postmortem brain tissue indicates the failure of microglia to phagocytose and degrade these pathological debris. "Frustrated" microglia might elicit the persistent immune responses and cause the neuronal deterioration in AD. The low incidence of AD in rheumatoid arthritis patients, who have received the long-term anti-inflammatory medication, supports this notion.

Alzheimer Disease↗
PubMed1997

Naturally occurring primary deficiencies of the immune system.

Naturally occurring genetic disorders of the immune system provide many models for the study of its development and function. In a way, their analysis complements the information provided by the generation of genetic defects in mice created using homologous recombination techniques. In this review, the recent findings made in three areas are focused upon deficiencies in T cell differentiation and in T lymphocyte activation, and on the control process of peripheral immune response.

Animals↗
PubMed1993

Immunologic approaches to assessing the response to inactivated hepatitis A vaccine.

Natural immunity to hepatitis A virus (HAV) is complex and likely to involve several distinct arms of the immune system. There is evidence that natural killer cells, human leukocyte antigen (HLA)-restricted cytotoxic T cells, and antibody-secreting cells of B-cell lineage all play roles in the immune response to infection with HAV. However, antibody alone is sufficient to provide a high level of protection against clinical disease. A comparison of the serum levels of antibody to HAV (anti-HAV) following administration of immune serum globulin and hepatitis A vaccine may provide a useful estimate of vaccine efficacy. Such comparisons may be accomplished using solid-phase immunoassays for detection of anti-HAV. However, tests which measure antibody capable of neutralizing virus in vitro are generally more sensitive than solid-phase immunoassays. The use of endogenously labelled virus in radioimmunoprecipitation assays shows promise of providing an equally sensitive means of measuring antibodies which are reactive with HAV particles.

Hepatitis A Antibodies↗
PubMed1996

Xenotransplantation: recent progress and current perspectives.

A severe shortage of human transplant donors has sparked interest in the use of animals as a source of organs and tissues for transplantation. Clinical application of xenotransplantation is limited in large part by the severe immunological reaction of the recipient against the graft. This immunological reaction is mediated initially by components of natural immunity such as xenoreactive antibodies, complement and natural killer cells and later by elicited humoral and cellular immune responses which act in concert to disrupt the function of the endothelial lining of blood vessels. The past few years have brought considerable progress in elucidating the molecular and cellular basis of xenograft rejection and in developing strategies to overcome xenograft rejection.

Acute Disease↗
PubMed1997

The prospects for xenotransplantation of the kidney.

A severe shortage of transplant donors has led to a markedly prolonged waiting time for renal transplantation and has thus sparked interest in the use of animals in lieu of humans as a source of kidneys for transplantation. Clinical application of xenotransplantation is limited in large part by the severe immunologic reaction of the recipient against the graft. This immunologic reaction is mediated initially by components of natural immunity, such as xenoreactive antibodies, complement and natural killer cells, and later by elicited humoral and cellular immune responses that act in concert to disrupt the function of the endothelial lining of blood vessels. The past few years have brought considerable progress in elucidating the molecular and cellular basis of xenograft rejection and in developing strategies to overcome it.

Animals↗
PubMed1987

Antibodies to a streptococcal antigen in gingival capillary and crevicular fluid washings, collected from man and non-human primates.

The local gingival antibody response was examined in actively-immunized rhesus monkeys and in human natural immunization to the cell-surface streptococcal antigen (SA I/II). A technique was developed to collect gingival capillary and crevicular fluid washings (GCCFW) from monkeys and human subjects with clinically normal gingiva. The thin crevicular epithelium and the adjacent capillary plexus are pierced with a probe and the resulting mixture of capillary blood, tissue fluid and crevicular fluid are collected by repeated washing of the gingival crevice. Antibodies measured by a solid-phase radioimmunoassay revealed that the IgG class of anti-SA I/II antibodies in GCCFW from the entire gingiva were positively correlated with the corresponding serum antibodies. Antibody levels from six defined dento-gingival units showed a progressive increase in the anti-SA I/II antibody level from the incisor to the premolar and molar units. A significant negative correlation was found between the antibody level of the total GCCFW and past caries experience. A similar negative correlation was found between antibodies from the GCCFW and the DMFS index of the molar teeth. The results are consistent with the hypothesis that there is an independent local immune response in the dento-gingival unit, which is superimposed on the common circulating serum antibodies and sensitized lymphocytes.

Animals↗
PubMed2000

Sex hormone adjuvant therapy in rheumatoid arthritis.

RA is an autoimmune rheumatic disorder resulting from the combination of several predisposing factors, including the relation between epitopes of possible triggering agents and histocompatibility epitopes, the status of the stress response system, and the sex hormone status. Estrogens are implicated as enhancers of humoral immunity, and androgens and progesterone are natural immune suppressors. Sex hormone concentrations have been evaluated in RA patients before glucocorticoid therapy and have frequently been found to be altered, especially in premenopausal women and male patients. In particular, low levels of gonadal and adrenal androgens (testosterone and DHT, DHEA and DHEAS) and a reduced androgen:estrogen ratio have been detected in body fluids (i.e., blood, synovial fluid, smears, saliva) of male and female RA patients. These observations support a possible pathogenic role for the decreased levels of the immune-suppressive androgens. Exposure to environmental estrogens (estrogenic xenobiotics), genetic polymorphisms of genes coding for hormone metabolic enzymes or receptors, and gonadal disturbances related to stress system activation (hypothalamic-pituitary-adrenocortical axis) and physiologic hormonal perturbations such as during aging, the menstrual cycle, pregnancy, the postpartum period, and menopause may interfere with the androgen:estrogen ratio. Sex hormones might exert their immune-modulating effects, at least in RA synovitis, because synovial macrophages, monocytes, and lymphocytes possess functional androgen and estrogen receptors and may metabolize gonadal hormones. The molecular basis for sex hormone adjuvant therapy in RA is thus experimentally substantiated. By considering the well-demonstrated immune-suppressive activities exerted by androgens, male hormones and their derivatives seem to be the most promising therapeutic approach. Recent studies have shown positive effects of androgen replacement therapy at least in male RA patients, particularly as adjuvant treatment. Interestingly, the increase in serum androgen metabolism induced by RA treatment with CSA should be regarded as a possible marker of androgen-mediated immune-suppressive activities exerted by CSA, at least in RA and at the level of sensitive target cells and tissues (i.e., synovial macrophages). The absence of altered serum levels of estrogens in RA patients and the reported immune-enhancing properties exerted by female hormones have represented a poor stimulus to test estrogen replacement therapy in RA. The different results obtained with OC use seem to depend on dose-related effects and the different type of response to estrogens in relation to the cytokine balance between Th1 cells (cellular immunity, i.e., RA) and Th2 cells (humoral immunity, i.e., SLE). The androgen replacement obtained directly (i.e., testosterone, DHT, DHEAS) or indirectly (i.e., antiestrogens) may represent a valuable concomitant or adjuvant treatment to be associated with other disease-modifying antirheumatic drugs (i.e., MTX, CSA) in the management of RA.

Androgens↗
PubMed1992

Epidemiology and prevention of respiratory tract infections due to nonencapsulated Haemophilus influenzae.

Nonencapsulated Haemophilus influenzae cause mainly respiratory tract infections, including otitis, sinusitis, and pneumonia. These infections may become chronic or recurrent in patients with bronchitis or otitis. Patients are usually infected with one strain at a time. During recurrent otitis, H. influenzae isolates have an outer membrane protein composition different from that seen during earlier episodes. In chronic bronchitis, H. influenzae strains persist for up to 1 year. In addition, isolates with different outer membrane protein compositions have been obtained that are antigenic variants of previous isolates. The variations occur in outer membrane protein b,c (P2), d (P5), or both. The variable parts are immunodominant, and antibodies to these parts are bactericidal. Cross-reactive bactericidal antibodies to outer membrane proteins have been elicited in immunized animals. These data indicate that natural immunity to nonencapsulated H. influenzae is mainly strain-specific but also that biologically active cross-reactive antibodies can be elicited by immunization.

Antibodies, Bacterial↗
PubMed1999

Mucosal immunity and tolerance: relevance to vaccine development.

The mucosal immune system of mammals consists of an integrated network of lymphoid cells which work in concert with innate host factors to promote host defense. Major mucosal effector immune mechanisms include secretory antibodies, largely of immunoglobulin A (IgA) isotype, cytotoxic T cells, as well as cytokines, chemokines and their receptors. Immunologic unresponsiveness (tolerance) is a key feature of the mucosal immune system, and deliberate vaccination or natural immunization by a mucosal route can effectively induce immune suppression. The diverse compartments located in the aerodigestive and genitourinary tracts and exocrine glands communicate via preferential homing of lymphocytes and antigen-presenting cells. Mucosal administration of antigens may result in the concomitant expression of secretory immunoglobulin A (S-IgA) antibody responses in various mucosal tissues and secretions, and under certain conditions, in the suppression of immune responses. Thus, developing formulations based on efficient delivery of selected antigens/tolerogens, cytokines and adjuvants may impact on the design of future vaccines and of specific immunotherapeutic approaches against diseases associated with untoward immune responses, such as autoimmune disorders, allergic reactions, and tissue-damaging inflammatory reactions triggered by persistent microorganisms.

Adjuvants, Immunologic↗
PubMed1979

Immunity to tetanus and diphtheria in various age groups of the Polish population.

The concentration of tetanus and diphtheria antitoxins was determined in 279 sera of 18 to 81-year-old women and 509 sera of 22 to 46-year-old men. Tetanus antitoxin content was determined also in 246 samples of fluid from human placentas and 428 lots of commercial human normal immunoglobulins. Immunity to tetanus was clearly age-dependent: in younger age groups the percentage of immunized persons amounted to 90%-100%, in middle-age groups to about 80%, and at age above 60 to about 25%. The findings are in agreement with age-dependent incidence of tetanus, which has become now in Poland a disease primarily of older people. Two groups of the population are now protected against diphtheria: a younger group under 20, and an older one above 40. Immunity in younger age groups was induced by artificial immunization, and among older persons by natural immunization through contact with diphtheria bacilli during severe diphtheria epidemics in the past. Between these groups, gaps exist including 20-30 years of age, who are sensitive to diphtheria.

Adolescent↗
PubMed1997

The natural killer gene complex: a genetic basis for understanding natural killer cell function and innate immunity.

The natural killer gene complex encodes proteins, some of which are structurally unrelated, that impact on NK-cell function. Detailed analyses have indicated that these molecules are involved in NK-cell recognition, activation, and inhibition. The importance of this genomic region is highlighted by studies indicating that NKC-associated genes significantly influence NK cell-mediated innate host defense against life-threatening pathogens and that the NKC is conserved among diverse species. Thus, further elucidation of the NKC and its gene products will provide a genetic basis for understanding innate immunity and NK-cell activity at the molecular level.

Animals↗