Higher frequency of HIV-1-specific T cell immune responses in African American children vertically infected with HIV-1

The progression of human immunodeficiency virus (HIV) disease and plasma levels of HIV may differ between racial groups. We compared HIV-specific T cell responses between vertically HIV-1-infected Hispanic and African American children. Subjects were matched for sex, age, viral load, and CD4(+) cell count in 18 pairs; T cell responses were measured by cytokine-enhanced interferon- gamma assay. Peripheral blood mononuclear cells were stimulated with HIV consensus peptides from Gag, Nef, and Tat. The influence of ethnicity, sex, age, viral load, and CD4(+) cell count on T cell responses was determined through linear regression analyses. After adjustment for CD4(+) count, age, and log(10) viral load, African American children demonstrated significantly higher Gag responses (average, 486 spot-forming cells higher; P=.01) than Hispanic children; this was significantly driven by robust responses in African American girls near the age of puberty, many of whom carried the human leukocyte antigen class I B*58 allele.     

A centralized gene-based HIV-1 vaccine elicits broad cross-clade cellular immune responses in rhesus monkeys

One of the major challenges that must be met in developing an HIV-1 vaccine is devising a strategy to generate cellular immunity with sufficient breadth to deal with the extraordinary genetic diversity of the virus. Amino acids in the envelopes of viruses from the same clade can differ by >15%, and those from different clades can differ by >30%. It has been proposed that creating immunogens using centralized HIV-1 gene sequences might provide a practical solution to this problem. Such centralized genes can be generated by employing a number of different strategies: consensus, ancestral, or center of tree sequences. These computer-generated sequences are a shorter genetic distance from any two contemporary virus sequences than those contemporary sequences are from each other. The present study was initiated to evaluate the breadth of cellular immunity generated through immunization of rhesus monkeys with vaccine constructs expressing either an HIV-1 global consensus envelope sequence (CON-S) or a single patient isolate clade B envelope sequence (clade B). We show that vaccine immunogens expressing the single centralized gene CON-S generated cellular immune responses with significantly increased breadth compared with immunogens expressing a wild-type virus gene. In fact, CON-S immunogens elicited cellular immune responses to 3- to 4-fold more discrete epitopes of the envelope proteins from clades A, C, and G than did clade B immunogens. These findings suggest that immunization with centralized genes is a promising vaccine strategy for developing a global vaccine for HIV-1 as well as vaccines for other genetically diverse viruses.     

Safety and immunogenicity of an HIV-1 recombinant canarypox vaccine in newborns and infants of HIV-1-infected women

Pediatric AIDS Clinical Trials Group protocol 326 is a study of 2 formulations of recombinant canarypox ALVAC vaccine (vCP205) against human immunodeficiency virus type 1 (HIV-1). HIV-1-exposed infants were randomized to receive 1 of 2 formulations of vCP205 or placebo at birth and 4, 8, and 12 weeks. The vaccines were safe. Lymphoproliferative responses were detected at > or =2 time points in 44%-56% of vaccinees and none of the placebo recipients. A cytotoxic T lymphocyte response on at least 1 occasion was detected in 62.5% of infants in cohort 1 (10(6.08) median tissue culture dose [TCID(50)] vaccine formulation) and 44% of infants in cohort 2 (10(6.33) TCID(50) vaccine formulation). Rare mucosal immunoglobulin A responses and no measurable vaccine-elicited serum antibodies were detected. In children, vCP205 appeared to be safe and immunogenic.     

多发性骨髓瘤MUC1-2VNTR基因疫苗诱导小鼠免疫应答的实验研究

目的观察黏蛋白1两串联重复区（MUC1-2VNTR）基因疫苗诱导BALB／c小鼠体液及细胞免疫应答的效果。方法将含MUC12VNTR的重组质粒peDNA3．1-2VNTR／myc-hisB免疫小鼠,免疫后采用ELISA动态检测血清中抗VNTR特异性抗体的水平,乳酸脱氢酶法检测细胞毒性T细胞（CTL）反应活性,MTS法检测脾淋巴细胞增殖活性。结果重组质粒免疫组小鼠血清中检出了MUC1-2VNTR抗原特异性抗体。用重组质粒免疫BALB／c小鼠后,在效靶比为80：1时可显著地诱导特异性CTL应答。在MUC1-2VNTR抗原肽的刺激下,免疫小鼠脾淋巴细胞得到增殖;与空质粒对照组比较,差异有统计学意义（P〈0．01）。结论MUC1-2VNTR基因疫苗可诱导小鼠产生特异性细胞及体液免疫应答,对多发性骨髓瘤的疫苗治疗有重要意义。     

T-cell responses induced in normal volunteers immunized with a DNA-based vaccine containing HIV-1 env and rev

OBJECTIVE: An effective HIV-1 vaccine will likely need to induce strong cell-mediated immunity in humans. Therefore, we examined the ability of a DNA HIV-1 vaccine to induce a T-cell response in HIV-1 seronegative humans. DESIGN: Individuals were enrolled in a phase I clinical trial of safety and immune responses to an env/rev-containing plasmid at doses of 100, 300 or 1000 microg. Peripheral blood mononuclear cells (PBMC) samples were analyzed by standard lymphocyte proliferation, cytotoxic T lymphocyte (CTL) and ELISPOT techniques. RESULTS: PBMCs from subjects immunized with doses as low as 300 microg proliferated in vitro to env (four of six) or (three of six) proteins. Importantly, when the dose of vaccine was increased to 1000 microg of DNA, lymphocytes secreted IFN-gamma in an ELISPOT assay following in vitro stimulation with env (three of six) or rev (four of six) proteins. CONCLUSION: We observed HIV-1 DNA plasmid vaccines induce CD4 T-helper cell responses in humans. We observed a discrepancy in the CD4 versus CD8 response suggesting the importance of analyzing both compartments in clinical evaluation. Furthermore, this report demonstrates the high level of immunogenicity of and its importance as a component of a prophylactic vaccine for HIV-1.     

Cell-mediated immune responses to autologous virus in HIV-1-seropositive individuals after treatment with an HIV-1 immunogen

OBJECTIVE: We hypothesized that cell mediated immune responses to an HIV-1 immunogen (whole-killed, gp120-depleted HIV-1 in IFA, REMUNE) would include those to autologous virus. METHODS: Five chronically HIV-1 infected individuals were examined for HIV-specific immune responses to their own virus (autologous viral antigen) after treatment with an HIV-1 immunogen. RESULTS: Subjects had low proliferative responses to HIV and p24 antigens prior to immunization and mounted strong lymphocyte proliferative responses to the immunizing HIV-1 virus, native p24, and autologous viral antigen post immunization. Similarly, subjects produced low amounts of interferon-gamma in response to HIV and p24 antigens prior to immunization and increased their interferon-gamma production in response to HIV-1, native p24, and to autologous antigen post-immunization. Furthermore, beta-chemokine responses measured as migratory inhibitory protein-1beta production were low at baseline in response to HIV-1 and native p24 antigens and were enhanced post immunization to HIV-1, native p24, and autologous antigen. CONCLUSIONS: In this study HIV-specific immune responses to autologous virus were observed after treatment with an HIV-specific immunogen.     

Cellular HIV-1 immune responses in natural infection and after genetic immunization

By eliminating infected cells, virus-specific cytotoxic T-lymphocytes (CTL) play a central role in host protection. Many studies to date seem to support the concept that human immunodeficiency virus (HIV)-specific CTL responses contribute to the control of viral replication, and thus delay the onset of disease. The feasibility of improving the virus-specific T-cell immunity by immunizing during the asymptomatic phase of infection has been studied in man. DNA vaccination is a novel strategy, involving direct inoculation of genetic material that is capable of producing antigen intracellularly for presentation to CTL. Such DNA-based immunization has been shown in animal models to be effective for the induction of both cellular and humoral immune responses as well as for protection from infectious challenge. This article reviews the cell-mediated immune responses in natural HIV-1 infection and the induction by DNA vaccination in humans.     

Safety and immunogenicity of Bacillus Calmette-Guerin vaccine in children born to HIV-1 infected women

This prospective cohort study was conducted to determine the complication of Bacillus Calmette-Guerin (BCG) vaccination given to newborn infants born to HIV-1 seropositive mothers and to compare the tuberculin reaction 9 months after BCG vaccination between HIV-1 infected and non infected children. Two hundred and twenty-three infants with BCG immunization at birth were examined. No BCG complication was noted. Tuberculin skin tests were performed on 126 children (56.5%). Eleven of them were excluded because of failure to have skin tests read at 48 hours. Of the 115 infants enrolled to this study, 15 (13%) had no BCG scar and 50 (43.5%) had no tuberculin reaction. Twenty-six children were classified as group 1 or HIV-1 infected children and 89 children were group 2 or HIV-1 non infected. Group 1 children had a smaller tuberculin skin response (X+SD) than group 2 (1.15 +/- 2.82 vs 4.64 +/- 4.29 mm; p < 0.0001). Mean weight + SD of group 1 children was also significantly less than those in group 2 (8,013 +/- 741 vs 8,540 +/- 984 g; p < 0.05). The proportion of children with non reactivity to the tuberculin test, a negative tuberculin test and no BCG scar in group 1 was significantly higher than that in group 2 (76.9% vs 33.7%, 92.3% vs 52.8% and 36.4% vs 6.7% respectively; p < 0.0001 for all). But, the proportion of non reactivity to the tuberculin test in children with or without BCG scar of each group was not different (p > 0.05). Positive tuberculin tests were 7.7% and 47.2% in group 1 and 2 respectively. None of the children with positive tuberculin tests had clinical evidence of tuberculosis. The findings of this study indicate that BCG vaccine given to newborn infants of HIV-1 seropositive mothers is safe. Although tuberculin skin responses of HIV-1 infected children are less than those of HIV-1 non-infected children, it is possible that BCG vaccine might protect these children from developing severe tuberculosis.     

Different T helper type immune responses induced by Helicobacter pylori vaccine in mouse model

OBJECTIVE: To study the protective immune response induced by Helicobacter pylori vaccine in mice. METHODS: Mice were orally immunized with cholera toxin (CT) plus H. pylori whole‐cell sonicate antigen (group A), CT only (group B) or normal saline (group C), and challenged with H. pylori 4 weeks later. Mice from each group were killed at different time points before and after challenge. Gastric H. pylori colonization, serum anti‐H. pylori IgG1, IgG2a and IgA antibodies, the mRNA expression of both Th1‐type and Th2‐type cytokines in the gastric mucosa and splenic tissue, and mucosal inflammation at different time points were compared among the groups. RESULTS: Colonization of H. pylori in group A decreased significantly compared with groups B and C at both 5 and 26 weeks after challenge. The serum concentrations of anti H. pylori IgG1, IgG2a and IgA in group A were significantly higher than those of groups B and C at all time points. The mRNA expressions of Th1‐type cytokines in the gastric mucosa of groups A and B were higher than those of group C both before and 5 weeks after H. pylori challenge. At 26 weeks after challenge, Th1‐type cytokines were increased in the gastric mucosa of group C, but decreased in the gastric mucosa of groups A and B, except for IL‐12. Before challenge, Th2‐type cytokines were expressed at a similar level in the gastric mucosa of both group A and group B; 5 weeks after challenge, IL‐4 and IL‐10 expressions were not detectable in either group and the expression of IL‐6 in both groups was lower than that in group C; 26 weeks after challenge, the expression of both IL‐4 and IL‐10 was detected in group A, but only IL‐10 in group B. The expression of IL‐6 was similar in all groups. Both Th1‐ and Th2‐type cytokines were expressed in the splenic tissue of all groups at different time points. Significant gastritis characterized by marked infiltration of mononuclear cells and neutrophils was found in group A at 5 weeks after challenge, but only mild inflammation was present in group B; 26 weeks after challenge, gastritis had increased in group C but decreased in the other two groups. CONCLUSIONS: The vaccine consisting of H. pylori whole‐cell sonicate antigen and CT induces both Th1 and Th2 immune responses at an early stage. The Th1 response increases early after H. pylori challenge, which contributes to both protective immunity and postimmunization gastritis, whereas the Th2 response increases in the gastric mucosa late after challenge when both the Th1 response and postimmunization gastritis have abated.     

Correlation between immunologic responses to a recombinant glycoprotein 120 vaccine and incidence of HIV-1 infection in a phase 3 HIV-1 preventive vaccine trial

BACKGROUND: An objective of the first efficacy trial of a candidate vaccine containing recombinant human immunodeficiency virus (HIV) type 1 envelope glycoprotein 120 (rgp120) antigens was to assess correlations between antibody responses to rgp120 and the incidence of HIV-1 infection. METHODS: Within the randomized trial (for vaccinees, n=3598; for placebo recipients, n=1805), binding and neutralizing antibody responses to rgp120 were quantitated. A case-cohort design was used to study correlations between antibody levels and HIV-1 incidence. RESULTS: Peak antibody levels were significantly inversely correlated with HIV-1 incidence. The relative risk (RR) of infection was 0.63 (95% confidence interval, 0.45-0.89) per log(10) higher neutralization titer against HIV-1(MN), and the RRs of infection for second-, third-, and fourth-quartile responses of antibody blocking of gp120 binding to soluble CD4 versus first-quartile responses (the lowest responses) were 0.35, 0.28, and 0.22, respectively. CONCLUSIONS: Despite inducing a complex, robust immune response, the vaccine was unable to reduce the incidence of HIV-1. Two interpretations of the correlative results are that the levels of antibodies (i) caused both an increased (low responders) and decreased (high responders) risk of HIV-1 acquisition or (ii) represented a correlate of susceptibility to HIV-1 but had no causal effect on susceptibility. Although the data cannot definitively discriminate between these 2 explanations, (ii) appears to be more likely.     

Reduction of anti-HIV-1 Gag immune responses during co-immunization: immune interference by the HIV-1 envelope

Immunization with more than one immunogen (co-immunization) is an efficient regimen to induce immunity to multiple antigens. However, immune interference has been reported using multi-plasmid DNA immunizations. HIV-1 envelope (Env) and Gag gene products are the predominant immunogens used in current AIDS vaccines, although, few studies have evaluated possible immune interference when these two antigens are co-administered. Therefore, in this study, immune interference during co-inoculation was examined using DNA vaccines expressing lentiviral Envs and Gag from gene sequences optimized for efficient expression in mammalian cells (codon-optimized). BALB/c mice vaccinated in separate hind legs with each plasmid individually elicited high titer immune responses, however, when HIV-1 Env(gp120) and HIV-1 Gag(p55) DNA plasmids were co-inoculated, there was a reduction in the immune responses elicited to HIV-1 Gag(p55). To determine if the anti-HIV-1 Gag(p55) immune interference was specific to HIV-1 Env(gp120), mice were co-immunized with plasmids expressing the surface envelope protein from two additional lentiviruses, Env(gp130)-SIV or Env(gp90)-EIAV, or a soluble form of hemagglutinin (sHA) from influenza virus and HIV-1 Gag(p55)- or SIV Gag(p55)-DNA. Interestingly, there was no reduction in anti-HIV-1 Gag(p55) immune responses using other lentiviral envelopes or the influenza sHA. Also, none of the lentiviral envelopes reduced anti-SIV Gag(p55) immune responses during co-immunization. Therefore, anti-HIV-1 Gag immune interference appears specific to co-immunizations with HIV-1 Env(gp120) and may involve a yet undefined immunological mechanism(s).     

Mucosal immune responses in the genital tract of HIV-1-exposed uninfected women

The development of HIV-1 vaccines and microbicides remains hindered by our limited understanding of correlates of immune protection to infection. Evidence indicating that resistance to HIV-1 infection is indeed possible comes from HIV-1-exposed yet uninfected individuals, including cohorts of commercial sex workers and discordant couples. Despite their uninfected status some of these individuals have mucosal and systemic HIV-1-specific humoral and cellular immune responses in addition to their innate immune response. The combined contribution of innate and adaptive immunity as well as genetic factors is most likely of great importance for this protection against infection. Here we review data on the antibody responses and secreted immune molecules of the innate immune system in the female genital tract with emphasis on individuals who seem to resist HIV-1-infection despite repeated exposure to the virus.     

HBV DNA vaccine with adjuvant cytokines induced specific immune responses against HBV infection

AIM: To seek for an effective method to improve the immuneresponses induced by DNA vaccine expressing HBV surfaceantigen (pCR3.1-S) in Balb/c mice (H-2d).METHODS: The pCR3.1-S plasmid and the eukaryoticexpression vectors expressing murine IL-2 (pDOR-IL-2) orIL-12 (pWRG3169) were injected into mice subcutaneously.The immune responses to pCR3.1-S and the adjuvant effectof the cytokines plasmid were studied. Meanwhile the effectof pCR3.1-S on anti-translated subcutaneous tumor of P815mastocytoma cells stably expressing HBsAg (P815-HBV-S)was also studied. Anti-HBs in serum was detected by enzyme-linked immunoadsordent assay (ELISA) and HBsAg specificcytotoxic T lymphocytes (CTLs) activity was measured by 51Crrelease assay. After three weeks of DNA immunization, thecells of P815-HBV-S were inoculated into mice subcutaneouslyand the tumor growth was measured every five days. Thesurvival rate and living periods of mice were also calculated.RESULTS: After 8 wk DNA immunization, the ,4 450 nmvalues of sera in mice immunized with pCR3.1, pCR3.1-Sand pCR3.1-S codeliveried with IL-2 or IL-12 plasmids were0.03±0.01, 1.24±0.10, 1.98±0.17 and 1.67±0.12respectively. Data in mice codeliveried pCR3.1-S with IL-2or IL-12 plasmids were significantly higher than that of miceinjected pCR3.1 or pCR3.1-S only. The HBsAg specific CTLactivities in mice coinjected with pCR3.1-S and IL-2 or IL-12 eukaryotic expression vectors were (61.9±7.1) % and(73.3±8.8) %, which were significantly higher than that ofmice injected with pCR3.1 (10.1±2.1) % or pCR3.1-S (50.5±6.4) %. The HBsAg specific CTL activities in mice injectedwith pCR3.1, pCR3.1-S, pCR3.1-S combined with IL-2 or IL-12 eukaryotic expression vectors decreased significantly to(3.2±0.8) %, (10.6±1.4) %, (13.6±1.3) % and (16.9±2.3)% respectively after the spleen cells were treated by anti-CD8+ monoclonal antibody, but presented no significantchange to anti-CD4+ monoclonal antibody or unrelated tomonoclonal antibody. The HBV-S DNA vaccine (pCR3.1-S)could evidently inhibit the tumor growth, prolong the survivalperiod of mice and improve the survival rate of mice andthese effects could be improved by IL-12 gene codeliveried.CONCLUSION: HBV DNA vaccine has a strong antigenicityin humoral and cellular immunities, which can be promotedby plasmid expressing IL-2 or IL-12. CD8+ cells executedthe CTL activities. DNA vaccine may be useful for bothprophylaxis and treatment of HBV infection.     

HBV DNA vaccine with adjuvant cytokines induced specific immune responses against HBV infection

AIM: To seek for an effective method to improve the immuneresponses induced by DNA vaccine expressing HBV surfaceantigen (pCR3.1-S) in Balb/c mice (H-2d).METHODS: The pCR3.1-S plasmid and the eukaryoticexpression vectors expressing murine IL-2 (pDOR-IL-2) orIL-12 (pWRG3169) were injected into mice subcutaneously.The immune responses to pCR3.1-S and the adjuvant effectof the cytokines plasmid were studied. Meanwhile the effectof pCR3.1-S on anti-translated subcutaneous tumor of P815mastocytoma cells stably expressing HBsAg (P815-HBV-S)was also studied. Anti-HBs in serum was detected by enzyme-linked immunoadsordent assay (ELISA) and HBsAg specificcytotoxic T lymphocytes (CTLs) activity was measured by 51Crrelease assay. After three weeks of DNA immunization, thecells of P815-HBV-S were inoculated into mice subcutaneouslyand the tumor growth was measured every five days. Thesurvival rate and living periods of mice were also calculated.RESULTS: After 8 wk DNA immunization, the ,4 450 nmvalues of sera in mice immunized with pCR3.1, pCR3.1-Sand pCR3.1-S codeliveried with IL-2 or IL-12 plasmids were0.03±0.01, 1.24±0.10, 1.98±0.17 and 1.67±0.12respectively. Data in mice codeliveried pCR3.1-S with IL-2or IL-12 plasmids were significantly higher than that of miceinjected pCR3.1 or pCR3.1-S only. The HBsAg specific CTLactivities in mice coinjected with pCR3.1-S and IL-2 or IL-12 eukaryotic expression vectors were (61.9±7.1) % and(73.3±8.8) %, which were significantly higher than that ofmice injected with pCR3.1 (10.1±2.1) % or pCR3.1-S (50.5±6.4) %. The HBsAg specific CTL activities in mice injectedwith pCR3.1, pCR3.1-S, pCR3.1-S combined with IL-2 or IL-12 eukaryotic expression vectors decreased significantly to(3.2±0.8) %, (10.6±1.4) %, (13.6±1.3) % and (16.9±2.3)% respectively after the spleen cells were treated by anti-CD8+ monoclonal antibody, but presented no significantchange to anti-CD4+ monoclonal antibody or unrelated tomonoclonal antibody. The HBV-S DNA vaccine (pCR3.1-S)could evidently inhibit the tumor growth, prolong the survivalperiod of mice and improve the survival rate of mice andthese effects could be improved by IL-12 gene codeliveried.CONCLUSION: HBV DNA vaccine has a strong antigenicityin humoral and cellular immunities, which can be promotedby plasmid expressing IL-2 or IL-12. CD8+ cells executedthe CTL activities. DNA vaccine may be useful for bothprophylaxis and treatment of HBV infection.     

Evaluation of cellular immune responses in subjects chronically infected with HIV type 1

The importance of host cellular immune responses, particularly CD8(+) cytotoxic T-lymphocyte (CTL) responses, in control of human immunodeficiency virus type 1 (HIV-1) infection has been demonstrated in many clinical studies. These studies, along with vaccination challenge studies in rhesus macaques, indicate the importance of cellular immune responses against HIV-1. Toward this end, we evaluated anti-HIV-1 cellular immune responses in a cohort of 54 subjects who were chronically infected with HIV-1. By validation of IFN-gamma ELISpot assay, we established a dual cut-off criterion for scoring a positive response. The magnitude and frequency of cellular immune responses were measured against HIV-1 antigens (Gag, Pol, Nef, Rev, and Tat), using synthetic peptides as antigens in ELISpot assay. Here we showed that HIV-1 Gag, Pol, and Nef were frequent targets of T cell responses in these subjects, whereas Tat and Rev were less frequently recognized. We further evaluated the possible association between host cellular immune responses and corresponding plasma viral loads in this cohort. By performing ranking correlation analysis, we demonstrated a positive correlation between host viral loads and ELISpot responses of HIV Gag and Pol in untreated subjects. For the subjects under antiviral regimens, however, we did not find any significant association. Our findings suggest that the high levels of ELISpot responses in chronically infected subjects were reflective of their persistent viral infection.     

Analysis of the immune responses in chimpanzees infected with HIV type 1 isolates

The mechanisms of resistance to AIDS development in HIV-1-infected chimpanzees have remained elusive. Unique among chimpanzees naturally or experimentally infected with HIV, several animals of the Yerkes cohort have progressed to clinical AIDS with selection of isolates showing increased pathogenicity for chimpanzees. We compared progressors vs. nonprogressors among the HIV-infected chimpanzees that made up this cohort, eight of which have been infected with HIV-1 for over 14 years. The additional two progressors were infected de novo with chimpanzee-pathogenic HIV, rapidly leading to a progressor status. Nonprogressors were characterized by normal CD4(+) T cell counts and the absence of detectable viremia. In contrast, progressor chimpanzees had relatively high plasma viral loads associated with a dramatic loss of CD4(+) T cells. The analysis of immune responses showed a similar amplitude and breadth of ELISPOT T cell responses in both groups. HIV-specific proliferative responses were, however, absent in the progressor animals, which also exhibited increased levels of immune activation characterized by elevated levels of the circulating chemokines IP-10 and MCP-1. Of interest was the conservation of potent NK cell activity in all animals, potentially contributing to the extended symptom-free survival of progressor animals. Modest anti-HIV antibody titers were detectable in the nonprogressor group, but these antibodies exhibited good neutralizing activity. In progressors, however, two sets of data were noted: in animals that gradually selected for pathogenic isolates, or that were superinfected, very high neutralizing antibody titers were observed, although none to the pathogenic HIV. In contrast, two animals infected de novo with chimpanzee pathogenic HIV failed to mount an extensive humoral response and both failed to develop neutralizing antibodies to the virus. Taken together, pathogenic HIV infection in chimpanzees is associated with rapid loss of CD4(+) T cells and proliferative responses as well as higher levels of immune activation.