S100, CD68, and MHC class II molecule expression in cervical high- and low-grade HPV-induced lesions

INTRODUCTION: Some human papillomavirus (HPV) types are involved in malignant processes in the cervical epithelium, with 99% of cases attributed to oncogenic HPV infection. This study aimed to detect S100, CD68, and major histocompatibility complex class II (MHC-II) molecules in cervical uterine epithelial samples in patients with high- and low-grade lesions induced by HPV. METHODS: Fifty-eight samples from patients who were confirmed positive or negative for high-risk oncogenic HPV DNA, had histopathological diagnosis of cervical intraepithelial neoplasia (CIN) of grades I, II, or III, or were negative for intraepithelial lesion or malignancy were subjected to immunohistochemistry reaction to S100 protein, CD68, and MHC-II (HLA-DR alpha chain). RESULTS: The presence of MHC-II predominated in samples exhibiting histopathological alterations (p < 0.05). S100 detection was more numerous in carcinoma samples (CIN III) (75%). Presence of this protein correlated significantly (p < 0.05) with histopathological findings and viral load. CONCLUSIONS: A small expression of CD68 was observed, which may be explained by the observation in our study having been made on random microscopic fields and not on specific areas. The findings, such as the presence of S100 protein and MHC-II expression in samples with histological alterations, could suggest that the immune system fails to control HPV replication at the early stages of infection. Further studies with larger prospective data are necessary to confirm this result.

Immunopathology of american cutaneous leishmaniasis. Modulation of MHC class II gene products by Keratinocytes before and after glucantime therapy

Epidermal changes from 32 cutaneous and 3 mucosal American leishmaniasis (ACL) active lesions were studied for HLA-DR, -DP expression, Lanerhans cells and lymphocyte infiltration. In addition to a DR and DQ positivity at the surface of the cells of the inflammatory infiltrate, a strong reaction for DR antigens was detected on keratinocytes. Hyperplasia of Langerhans cells was present in al cutaneous lesions and epidermis was infiltrated by T lymphocytes. When healed lesions of 14 of these subjects were re-biopsied 1 to 12 months after the end of pentavalent antimonial therapy, MHC class antigens could no longer be seen on keratinocytes. Our data represrn evidence for hhe reversibility of the abnormal HLA-DR expression by keratinocytes in ACL after Glucantime therapy or spontaneous scar formation, demonstrating that this expresion is restricted to the period of active lesions. The present findings can be regarded as an indirect evidence that keratinocytes may be involved in the immunopathology of ACL.

Analysis of human leukocyte antigens class II-DR in Brazilian children and adolescents with systemic lupus erythematosus

OBJECTIVE: To analyze the frequency of human leukocyte antigens class II-DR in children and adolescents with systemic lupus erythematosus. PATIENTS AND METHODS: Fifty-fiveBrazilian systemic lupus erythematosus children and adolescents and 308 healthy individuals were studied. Gender, race, and age of onset of systemic lupus erythematosus were recorded. The human leukocyte antigens typing of class II-DR was carried out by polymerase chain reaction amplification with sequence-specific primers (PCR-SSP). Data were analyzed statistically using the chi square test with Yates' correction, Fisher's exact test, and Bonferroni's correction. RESULTS: Human leukocyte antigen-DR 15 was the most frequently detected antigen in this group of children and adolescents, and it also occurred more frequently in the female group, in children with onset of systemic lupus erythematosus between 0 and 9 years and between 10 to 14 years, and in the Black race group, but these associations were not statistically significants. CONCLUSION: In this group of children and adolescents with a high degree of racial admixture, we could not verify a significant association between human leukocyte antigens class II-DR and systemic lupus erythematosus.

Association analysis of human leukocyte antigen class II (DRB1) alleles with leprosy in individuals from São Luís, state of Maranhão, Brazil

Epidemiological studies have demonstrated that the variability of the clinical response to infection caused by Mycobacterium leprae is associated with host genetic factors. The present study investigated the frequency of human leukocyte antigen (HLA) class II (DRB1) alleles in patients with leprosy from São Luís, Maranhão, Brazil. A case-control study was performed in 85 individuals with leprosy and 85 healthy subjects. All samples were analysed via polymerase chain reaction-sequence specific oligonucleotide probes. The HLA-DRB1*16 allele showed a higher frequency in the group with leprosy [(9.41% vs. 4.12%) odds ratio (OR) = 2.41 95% confidence interval (CI) (0.96-6.08) p = 0.05], whereas the HLA-DRB1*11 allele was less frequent in the group with leprosy [(6.47% vs. 11.76%) OR = 0.51 95% CI (0.23-1.12) p = 0.09]. The frequency of HLA-DRB1* alleles between the control group and leprosy patient subgroups presenting different forms of the disease showed that the HLA-DRB1*16 (16.13% vs. 8.24%, OR = 4.10, CI = 1.27-13.27, p = 0.010) and HLA-DRB1*14 (5% vs. 3.53%, OR = 4.63, CI = 1.00-21.08, p = 0.032) alleles were significantly more frequent in patients with different clinical subtypes of leprosy. The sample size was a limitation in this study. Nevertheless, the results demonstrated the existence of a genetic susceptibility associated with the clinical forms of leprosy. The low frequency of the HLA-DRB1*11 allele should be further studied to investigate the possible protective effect of this allele.

Distribution of the human leukocyte antigen class II alleles in Brazilian patients with chronic hepatitis C virus infection

Hepatitis C virus (HCV) infection is a global medical problem. The current standard of treatment consists of the combination of peginterferon plus ribavirin. This regimen eradicates HCV in 55% of cases. The immune response to HCV is an important determinant of disease evolution and can be influenced by various host factors. HLA class II may play an important role in immune response against HCV. The objective of the present study was to determine the distribution of HLA class II (DRB1 and DQB1) alleles, their association with chronic HCV infection and their response to interferon therapy. One hundred and two unrelated white Brazilian patients with chronic HCV infection, 52 responders (45 males and 7 females) and 50 non-responders (43 males and 7 females) to antiviral treatment, were included in the study. Healthy Brazilian bone marrow donors of Caucasian origin from the same geographic area constituted the control group (HLA-DRB1, N = 99 and HLA-DQB1, N = 222 individuals). HLA class II genotyping was performed using a low-resolution DRB1, DQB1 sequence-specific primer amplification. There were higher frequencies of HLA-DRB1*13 (26.5 vs 14.1%) and HLA-DQB1*02 (52.9 vs 38.7%) in patients compared with controls; however, these were not significantly different after P correction (Pc = 0.39 and Pc = 0.082, respectively). There was no significant difference between the phenotypic frequencies of HLA-DRB1 (17.3 vs 14.0%) and HLA-DQB1 alleles in responder and non-responder HCV patients. The HLA-DRB1*07 allele was significantly more common in HCV patients (33.3 vs 12.1%) than in controls (Pc = 0.0039), suggesting that the HLA-DRB1*07 allele is associated with chronic HCV infection.

Modulation of B lymphocyte function by an aqueous fraction of the ethanol extract of Cissampelos sympodialis Eichl (Menispermaceae)

Cissampelos sympodialis Eichl species are used in folk medicine for the treatment of asthma, arthritis and rheumatism. In the present study, we investigated the immunomodulatory effect of an aqueous fraction of a 70% (v/v) ethanol extract of C. sympodialis leaves on B lymphocyte function. The hydroalcoholic extract inhibited the in vitro proliferative response of resting B cells induced by LPS (IC50 = 17.2 µg/ml), anti-delta-dextran (IC50 = 13.9 µg/ml) and anti-IgM (IC50 = 24.3 µg/ml) but did not affect the anti-MHC class II antibody-stimulated proliferative response of B cell blasts obtained by stimulation with IL-4 and anti-IgM. Incubation with the hydroalcoholic extract used at 50 µg/ml induced a 700% increase in intracellular cAMP levels. IgM secretion by resting B cells (obtained from normal mice) and polyclonally activated B cells (obtained from Trypanosoma cruzi-infected animals) was inhibited by the hydroalcoholic extract. The latter were more sensitive to the hydroalcoholic extract since 6.5 µg/ml induced a 20% inhibition in the response of cells from normal mice while it inhibited the response of B cells from infected animals by 75%. The present data indicate that the alcoholic extract of C. sympodialis inhibited B cell function through an increase in intracellular cAMP levels. The finding that the hydroalcoholic extract inhibited immunoglobulin secretion suggests a therapeutic use for the extract from C. sympodialis in conditions associated with unregulated B cell function and enhanced immunoglobulin secretion. Finally, the inhibitory effect of the hydroalcoholic extract on B cells may indicate an anti-inflammatory effect of this extract.

Low expression of antigen-presenting and costimulatory molecules by lung cells from tuberculosis patients

Costimulatory and antigen-presenting molecules are essential to the initiation of T cell immunity to mycobacteria. The present study analyzed by immunocytochemistry, using monoclonal antibodies and alkaline phosphatase-anti-alkaline phosphatase method, the frequency of costimulatory (CD86, CD40, CD40L, CD28, and CD152) and antigen-presenting (MHC class II and CD1) molecules expression on human lung cells recovered by sputum induction from tuberculosis (TB) patients (N = 22) and non-TB controls (N = 17). TB cases showed a statistically significant lower percentage of HLA-DR+ cells than control subjects (21.9 ± 4.2 vs 50.0 ± 7.2%, P < 0.001), even though similar proportions of TB cases (18/22) and control subjects (16/17, P = 0.36) had HLA-DR-positive-stained cells. In addition, fewer TB cases (10/22) compared to control subjects (16/17) possessed CD86-expressing cells (P = 0.04; OR: 0.05; 95%CI = 0.00-0.51), and TB cases expressed a lower percentage of CD86+ cells (P = 0.04). Moreover, TB patients with clinically limited disease (£1 lobe) on chest X-ray exhibited a lower percentage of CD86-bearing cells compared to patients with more extensive lung disease (>1 lobe) (P = 0.02). The lower expression by lung cells from TB patients of HLA-DR and CD86, molecules involved in antigen presentation and activation of T cells, may minimize T cell recognition of Mycobacterium tuberculosis, fostering an immune dysfunctional state and active TB.

The nature of autoantigens

1. Autoimmunity in deisease is driven by autoantigen; 2. Cell surface molecules may stimulate autoreactive T-helpers if call II MHC is expressed; special factors may predispose to the ease of class II induction; 3. Soluble autoantigens may be focussed by primed B-cells and processed for presentation to T-cell; 4. autoantigenicity may be influenced by metabolic events: (a) Poorly iodinated thyroglobulin does not induce thyroiditis; (b) IgG rheumatoid arthritis has galactose deficient Fc oligosaccharides. Glycosylation defects may prove to have wide implications.

Virulence and the immune response in malaria

Many factors determine the virulence of a malaria infection. These include host innate resistance mechanisms and, with Plasmodium falciparum, the ability to cytoadhere to endothelial cells, form rosetts, and induce release of cytokines. The effect on virulence of acquired immune responses can be determined by Class I and Class II MHC-antigens; levels of immunological responsiveness may be determined too in other ways. The structure of parasite surface antigens and their great diversity modulate the immune response and influence parasite survival and hence virulence, and transmission to the vector.

The role of T cell subsets and cytokines in the regulation of intracellular bacterial infection

Cellular immune responses are a critical part of the host's defense against intracellular bacterial infections. Immunity to Brucella abortus crucially depends on antigen-specific T cell-mediated activation of macrophages, which are the major effectors of cell-mediated killing of this organism. T lymphocytes that proliferate in response to B. abortus were characterized for phenotype and cytokine activity. Human, murine, and bovine T lymphocytes exhibited a type 1 cytokine profile, suggesting an analogous immune response in these different hosts. In vivo protection afforded by a particular cell type is dependent on the antigen presented and the mechanism of antigen presentation. Studies using MHC class I and class II knockout mice infected with B. abortus have demonstrated that protective immunity to brucellosis is especially dependent on CD8+ T cells. To target MHC class I presentation we transfected ex vivo a murine macrophage cell line with B. abortus genes and adoptively transferred them to BALB/c mice. These transgenic macrophage clones induced partial protection in mice against experimental brucellosis. Knowing the cells required for protection, vaccines can be designed to activate the protective T cell subset. Lastly, as a new strategy for priming a specific class I-restricted T cell response in vivo, we used genetic immunization by particle bombardment-mediated gene transfer

Idiopathic focal segmental glomerulosclerosis and HLA antigens

The objective of the present study was to investigate a possible association between HLA class II antigens and idiopathic focal segmental glomerulosclerosis (FSGS). HLA-A, -B, -DR and -DQ antigens were determined in 19 Brazilian patients (16 white subjects and three subjects of Japanese origin) with biopsy-proven FSGS. Comparison of the HLA antigen frequencies between white patients and white local controls showed a significant increase in HLA-DR4 frequency among FSGS patients (37.7 vs 17.2%, P<0.05). In addition, the three patients of Japanese extraction, not included in the statistical analysis, also presented HLA-DR4. In conclusion, our data confirm the association of FSGS with HLA-DR4 previously reported by others, thus providing further evidence for a role of genes of the HLA complex in the susceptibility to this disease

A method for multiple sequential analyses of macrophage functions using a small single cell sample

Microbial pathogens such as bacillus Calmette-Guérin (BCG) induce the activation of macrophages. Activated macrophages can be characterized by the increased production of reactive oxygen and nitrogen metabolites, generated via NADPH oxidase and inducible nitric oxide synthase, respectively, and by the increased expression of major histocompatibility complex class II molecules (MHC II). Multiple microassays have been developed to measure these parameters. Usually each assay requires 2-5 x 10(5) cells per well. In some experimental conditions the number of cells is the limiting factor for the phenotypic characterization of macrophages. Here we describe a method whereby this limitation can be circumvented. Using a single 96-well microassay and a very small number of peritoneal cells obtained from C3H/HePas mice, containing as little as <=2 x 10(5) macrophages per well, we determined sequentially the oxidative burst (H2O2), nitric oxide production and MHC II (IAk) expression of BCG-activated macrophages. More specifically, with 100 µl of cell suspension it was possible to quantify H2O2 release and nitric oxide production after 1 and 48 h, respectively, and IAk expression after 48 h of cell culture. In addition, this microassay is easy to perform, highly reproducible and more economical.

Viral membrane fusion: is glycoprotein G of rhabdoviruses a representative of a new class of viral fusion proteins?

Enveloped viruses always gain entry into the cytoplasm by fusion of their lipid envelope with a cell membrane. Some enveloped viruses fuse directly with the host cell plasma membrane after virus binding to the cell receptor. Other enveloped viruses enter the cells by the endocytic pathway, and fusion depends on the acidification of the endosomal compartment. In both cases, virus-induced membrane fusion is triggered by conformational changes in viral envelope glycoproteins. Two different classes of viral fusion proteins have been described on the basis of their molecular architecture. Several structural data permitted the elucidation of the mechanisms of membrane fusion mediated by class I and class II fusion proteins. In this article, we review a number of results obtained by our laboratory and by others that suggest that the mechanisms involved in rhabdovirus fusion are different from those used by the two well-studied classes of viral glycoproteins. We focus our discussion on the electrostatic nature of virus binding and interaction with membranes, especially through phosphatidylserine, and on the reversibility of the conformational changes of the rhabdovirus glycoprotein involved in fusion. Taken together, these data suggest the existence of a third class of fusion proteins and support the idea that new insights should emerge from studies of membrane fusion mediated by the G protein of rhabdoviruses. In particular, the elucidation of the three-dimensional structure of the G protein or even of the fusion peptide at different pH's might provide valuable information for understanding the fusion mechanism of this new class of fusion proteins.

HLA-DRB1 alleles in juvenile-onset systemic lupus erythematosus: renal histologic class correlations

Human leukocyte antigens (HLA) DRB1*03 and DRB1*02 have been associated with systemic lupus erythematosus (SLE) in Caucasians and black populations. It has been observed that certain HLA alleles show stronger associations with SLE autoantibodies and clinical subsets, although they have rarely been associated with lupus renal histologic class. In the present study, HLA-DRB1 allele correlations with clinical features, autoantibodies and renal histologic class were analyzed in a cohort of racially mixed Brazilian patients with juvenile-onset SLE. HLA-DRB1 typing was carried out by polymerase chain reaction amplification with sequence-specific primers using genomic DNA from 55 children and adolescents fulfilling at least four of the American College of Rheumatology criteria for SLE. Significance was determined by the chi-square test applied to 2 x 2 tables. The HLA-DRB1*15 allele was most frequent in patients with renal, musculoskeletal, cutaneous, hematologic, cardiac, and neuropsychiatric involvement, as well as in patients positive for anti-dsDNA, anti-Sm, anti-U1-RNP, and anti-SSA/Ro antibodies, although an association between HLA alleles and SLE clinical features and autoantibodies could not be observed. The HLA-DRB1*17, HLA-DRB1*10, HLA-DRB1*15, and HLA-DRB1*07 alleles were significantly higher in patients with renal histologic class I, class IIA, class IIB, and class V, respectively. The present results suggest that the contribution of HLA- DRB1 alleles to juvenile-onset SLE could not be related to clinical or serological subsets of the disease, but it may be related to renal histologic classes, especially class I, class II A, class II B, and class V. The latter correlations have not been observed in literature.

Astrocytic and microglial response and histopathological changes in the brain of horses with experimental chronic Trypanosoma evansi infection

This study aimed to characterize astrocytic and microglial response in the central nervous system (CNS) of equines experimentally infected with T. evansi. The experimental group comprised males and females with various degrees of crossbreeding, ages between four and seven years. The animals were inoculated intravenously with 10(6) trypomastigotes of T. evansi originally isolated from a naturally infected dog. All equines inoculated with T. evansi were observed until they presented symptoms of CNS disturbance, characterized by motor incoordination of the pelvic limbs, which occurred 67 days after inoculation (DAI) and 124 DAI. The animals in the control group did not present any clinical symptom and were observed up to the 125th DAI. For this purpose the HE histochemical stain and the avidin biotin peroxidase method was used. Lesions in the CNS of experimentally infected horses were those of a wide spread non suppurative meningoencephalomyelitis.The severity of lesions varied in different parts of the nervous system, reflecting an irregular distribution of inflammatory vascular changes. The infiltration of mononuclear cells was associated with anisomorphic gliosis and reactive microglia was identified. The intensity of the astrocytic response in the CNS of the equines infected by T. evansi characterizes the importance of the performance of these cells in this trypanosomiasis. The characteristic gliosis observed in the animals in this experiment suggests the ability of these cells as mediators of immune response. The parasite, T. evansi, was not identified in the nervous tissues.