Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0019693 (HIV)
 170,526 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Pre- and post-immunization serum antibodies to pneumococcal polysaccharides (PPS) and tetanus toxoid (TT) were measured in 25 patients with persistent generalized lymphadenopathy and serum antibodies to the human immunodeficiency virus (HIV). The increase in post-immunization anti-PPS antibodies was lower than 40% in 16/25 patients. Isotype analysis indicated that the IgM, IgA, IgG2, but not the IgG1 antibody responses were lower in patients that in healthy controls, whereas pre-immunization values were similar. For TT, no difference was found between the patients and the healthy group in total and IgG1 antibody response whereas IgG4 response was lower in patients. No significant association was found between the defect in anti-PPS antibody response and associated thrush or constitutional symptoms or other immunological parameters. These findings suggest that defective response to a thymo-independent polysaccharide antigen is a distinctive consequence of HIV infection.
 ...
PMID:Impaired anti-pneumococcal antibody response in patients with AIDS-related persistent generalized lymphadenopathy. 365 22

The global community is close to achieving universal childhood immunization against a group of important childhood diseases--measles, tuberculosis, diphtheria, pertussis, tetanus and polio. In addition, polio has been targeted for eradication by the year 2000 and neonatal tetanus for elimination by 1995. There are targeted reductions in mortality and cases of measles by the same year. This paper addresses the difficult issue of how optimally to integrate these public health initiatives into local health care practices and beliefs. At the workshop on Global Immunization and Culture I presented the perspective of a physician who has worked with the Expanded Programme on Immunization and has understanding at a global level of the logistics of vaccine delivery. This paper serves as a counterpoint to others at the workshop by raising the question of whether routine vaccine delivery and special eradication efforts can be best carried out with a uniform, technologically based approach rather than extensive adaptation of the program to local conditions and beliefs. The reliance on a largely technological approach to control of these childhood diseases which occur in all societies independent of social behavior is contrasted with efforts to control HIV infection in which social structure and practices predict the occurrence of disease.
 ...
PMID:Global immunization--a medical perspective. 750 95

The design of an in vitro immunization system based on a synthetic heterotope immunogen, which was a peptide containing both T- and B-cell epitopes, that elicited a neutralizing, primary human humoral immune response against the human immunodeficiency virus (HIV-1) is reported here. This heterotope construct contained the major neutralizing B-cell epitope, within the V3 region of glycoprotein 120 (gp120), linked to a promiscuous helper T-cell epitope of tetanus toxin. The peptide was used to induce a human humoral in vitro immune response against the V3 region, using lymphocytes obtained from healthy, sero-negative blood donors. The in vitro immunized peripheral blood lymphocytes were Epstein-Barr virus infected and the antibody response to the synthetic peptide was evaluated using a solid-phase ELISA with the recombinant C-terminal fragment of gp120 (pB1, amino acid residues 287-467, derived from the HIV-1 LAI isolate). The heterotope construct yielded a significantly frequency of specifically immunized B cells, in contrast to the control immunizations with individual T and B epitopes, mixtures of these epitopes or no immunogen at all. This approach allowed us to generate human monoclonal antibodies, using lymphocytes derived from sero-negative donors, that cross-neutralized several HIV-1 strains, inhibited syncytia formation as well as prevented spreading of the viral infection from cell to cell. Thus, site-directed in vitro immunization using synthetic heterotopes might prove valuable in the dissection and induction of a protective humoral immune response.
 ...
PMID:Site-directed primary in vitro immunization: production of HIV-1 neutralizing human monoclonal antibodies from lymphocytes obtained from seronegative donors. 751 47

This study was performed in 77 HIV1 seropositive adult patients to characterise the IgA hyperglobulinaemia seen in the serum during the course of HIV infection. It was shown that both IgA1 and IgA2 subclass concentrations were simultaneously increased but the IgA1 increase was predominant. Secretory IgA (SIgA) concentration was significantly increased and IgA activity to gliadin, bovine serum albumin, and casein could be detected and was correlated with SIgA concentration. In contrast, IgA activity to cytomegalovirus and to tetanus toxoid did not correlate with total IgA concentration. These data suggest the presence of IgA from gut mucosal origin in the serum of these patients. Hyper IgA was inversely correlated with the CD4+ cell number. The increase of all parameters studied varied according to the total IgA concentration in the serum but was also directly related to the stage of immune deficiency in patients with hyper IgA.
 ...
PMID:Is there IgA of gut mucosal origin in the serum of HIV1 infected patients? 751 78

Activated T-cells expressing MHC class II surface antigens are able to present antigen and thus function as peptide-presenting cells (T-APCs). In this study we investigated whether antigen presentation by T-cells induced programmed cell death. As a model we used tetanus p30 peptide (aa 947-967)-specific, noncytotoxic CD4+ T-cell clones (C11 and C31). For experimental purposes these T-cell clones were stimulated (a) with p30 peptide-pulsed and fixed EBV-transformed antigen-presenting cells (B-APCs), (b) with p30-pulsed and fixed activated T-cells as APCs (as T-APCs we used either the T-cell clones themselves or an autologous T-cell clone (CT3) with p30 unrelated specificity), or (c) with soluble p30 peptide. The efficiency of antigen presentation was monitored by measuring proliferation as [3H]thymidine uptake. Apoptosis was measured by quantifying fragmented, cytoplasm DNA with the fluorescent dye 4,6-diamidino-2-phenylindole or by visualizing fragmented DNA by gel electrophoresis. Stimulation with p30-pulsed and fixed B-APCs or T-APCs induced proliferation but no apoptosis of the responding T-cells. However, stimulation of cloned T-cells with soluble peptide induced up-regulation of the FAS surface molecules and apoptosis, which was dependent on the peptide doses. Because cloned T-cells express HLA class II molecules, they can theoretically exert both functions at once: antigen presentation and antigen response when they are stimulated with soluble peptide. Because death by apoptosis is only seen under such circumstances, we suggest that T-cells simultaneously presenting and responding to an antigen die of apoptosis and thus contribute to the down-regulation of the immune response. Such phenomena might occur in HIV infection when activated CD4+ T-cells take up gp120 via their CD4 molecules, present it on their HLA class II surface antigens, and are simultaneously stimulated via their TCR.
 ...
PMID:Noncytotoxic human CD4+ T-cell clones presenting and simultaneously responding to an antigen die of apoptosis. 753 49

Adoptive transfer of human lymphoid cells into immunodeficient (SCID) mice lacking the ability to functionally rearrange T- and B-cell receptor genes constitutes a unique model to study and manipulate human immunocytes. We have investigated this model for the purpose of generating an antigen-specific primary humoral immune response. Peripheral blood lymphocytes (PBL) derived from blood donors were used to repopulate SCID mice, which subsequently were immunized with different B-cell epitopes coupled to either tetanus toxoid (TT), or to a promiscuous helper epitope of TT, or by incorporating the antigens into a liposome construct. By recruiting the necessary T-cell help found in the T-cell memory compartment against TT, primary immune responses were obtained against the hapten dinitrophenyl (DNP), the V3 loop peptide derived from glycoprotein (gp120) (HIV-1), the melanoma-associated GD2 ganglioside and ovine submaxillary mucin. The primary immune response against the GD2 ganglioside was induced by incapsulating TT into GD2-containing liposomes. These liposome constructs also allowed us to induce a high human IgG serotitre (3000-4000) against this normally not very immunogenic ganglioside.
 ...
PMID:Induction of primary antigen-specific immune reponses in SCID-hu-PBL by coupled T-B epitopes. 753 59

Peptides were synthesized which combined HIV-1 B-epitopes from gp41, p34pol and heterologous T-cell epitopes from hepatitis B virus (HBV) core or tetanus toxoid. Mixtures of these composite peptides and peptides representing single HIV-1 B-epitopes were used to immunize rabbits in an adjuvant-free immunization regimen. Fusion to T-cell epitopes made the HIV-1 B-epitopes immunogenic and high titers of anti-HIV-1 antibodies were reached. Efficient antibody response against an immunorecessive HIV-1 B-epitope from p34 pol introduced as a B+T-composite also developed in rabbits pre-immunized by composites of the same T-cell epitopes but with a B-epitope from gp41. Fusion changed the fine antigenicity of the epitopes, but at least part of the antibodies against gp41-containing B+T composites recognized whole viral gp160. Composite peptides stimulated T-cells in the majority of the immunized animals.
 ...
PMID:Immunogenic combinations of HIV-1 B- and heterologous T-cell epitopes. 753 71

The specificity of IgA against food, inhalant, bacterial and fungine antigens as well as for HIV-1 proteins was investigated in 14 HIV-1-infected children (CDC stage P-2) and 15 controls. IgA against food- and inhalant antigens as well as against tetanus toxoid were significantly more often present in the HIV positive children than in controls. No difference between the two groups was present for IgA against Candida albicans. A significant increase of substance P, a strong IgA synthesis inducing neuropeptide, was demonstrated in the plasma of HIV-1 infected children. In conclusion, high levels of IgA seem to reflect a complex immune dysfunction in which many factors are involved. The importance of neuroimmune dysregulation is discussed.
 ...
PMID:High levels of IgA in HIV-1-perinatally-infected children. Antigen specificity and possible role of increased substance P plasma levels. 753 87

Molecular and cellular requirements for antigen-specific isotype switch of human B cells have been investigated by mimicking signaling occurring in germinal centers. Peripheral blood mononuclear cells from healthy seronegative blood donors were first primary immunized in vitro, using a synthetic immunogen containing both a T and B cell epitope, which generated specific IgM-secreting B cells. We used the apex of the V3 loop of gp120 as B cell epitope linked to a promiscuous T helper epitope from tetanus toxin. In parallel, CD4+ T helper cell clones specific for the T epitope of the immunogen were established. In a secondary in vitro stimulation period, we co-cultured the antigen-specific T and B cells on CD32-transfected fibroblasts, together with an anti-CD40 monoclonal antibody. This resulted in isotype switching and human antigen-specific, IgG-secreting B cells were detected. This response was strictly dependent upon the presence of autologous T helper cells and the immunogen. Antigen-specific human B cells derived from this primary and secondary in vitro immunization were subsequently subjected to electrofield-induced somatic cell hybridization and hybridomas secreting human anti-V3 IgG monoclonal antibodies were isolated. One human antibody was further characterized and shown to be specific for the immunizing antigen with an affinity constant of 24 nM. This antibody also effectively neutralized different isolates of HIV-1, achieving a 50% neutralization at 0.46 microgram/ml.
 ...
PMID:Mimicking the humoral immune response in vitro results in antigen-specific isotype switching supported by specific autologous T helper cells: generation of human HIV-1-neutralizing IgG monoclonal antibodies from naive donors. 753 99

Patterns of cytokine expression were analyzed in polyclonal and antigenic responses in children with perinatal HIV infection. Responses of PBL to PMA and A23187 calcium ionophore studied in patients in different stages of HIV infection revealed reduced levels of IL-2 in HIV-infected children beginning before 6 mo of age, and age-dependent increases in expression of IL-4, IL-10, and IFN-gamma. The levels of IL-4, IL-10, and IFN-gamma expression did not differ significantly between HIV-infected and age-matched uninfected children of HIV-seropositive mothers, except for a small reduction in HIV-infected children in late stages of infection. Responses to PHA, HLA alloantigens, HIV envelope peptides T1 and P18, and tetanus toxoid were studied in PBMC derived from asymptomatic and mildly symptomatic HIV-infected children. IL-2, IFN-gamma, IL-4, and IL-5 expression was detected in PHA-stimulated PBMC from all analyzed patients. HIV-infected children who failed to respond to HLA alloantigens, tetanus toxoid, or the envelope peptides had lower numbers of CD4+ cells and expressed, on PHA stimulation, higher levels of IL-4 and IL-5 and lower levels of IL-2 and IFN-gamma than patients who responded to the antigenic stimulation. Results of these analyses suggest that cytokine expression in HIV-infected children depends on the character of the stimuli as well as the phenotype of PBMC, and indicate possible prevalence of Th2 Ag-specific responses during the progression of HIV-induced immunodeficiency.
 ...
PMID:Cytokine patterns during progression to AIDS in children with perinatal HIV infection. 756 Nov 17


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>