A human immunodeficiency virus type-1 (HIV-1) vaccine which is able to effectively prevent infection would be the most powerful method of extinguishing pandemic of the acquired immunodeficiency syndrome (AIDS). Yet, achieving such vaccine remains great challenges. The membrane-proximal external region (MPER) is a highly conserved region of the envelope glycoprotein (Env) gp41 subunit near the viral envelope surface, and it plays a key role in membrane fusion. It is also the target of some reported broadly neutralizing antibodies (bNAbs). Thus, MPER is deemed to be one of the most attractive vaccine targets. However, no one can induce these bNAbs by immunization with immunogens containing the MPER sequence(s). The few attempts at developing a vaccine have only resulted in the induction of neutralizing antibodies with quite low potency and limited breadth. Thus far, vaccine failure can be attributed to various characteristics of MPER, such as those involving structure and immunology; therefore, we will focus on these and review the recent progress in the field from the following perspectives: (1) MPER structure and its role in membrane fusion, (2) the epitopes and neutralization mechanisms of MPER-specific bNAbs, as well as the limitations in eliciting neutralizing antibodies, and (3) different strategies for MPER vaccine design and current harvests.
AIDS Vaccines ; chemistry ; immunology ; Antibodies, Neutralizing ; immunology ; HIV Antibodies ; immunology ; HIV Envelope Protein gp41 ; immunology ; HIV-1 ; chemistry ; immunology ; Humans

OBJECTIVETo describe and evaluate a double-antigen sandwich ELISA for detecting human immunodeficiency virus type 1/2 (HIV-1/2) specific antibodies.

METHODSThe peptides gp41.1(sp1), gp41.2(sp2), gp120(sp3) and p24(sp4) of HIV-1 and gp36(sp5) of HIV-2 were artificially synthesized. Then sp1, sp3, sp4 and sp5 were used as coating antigens; sp1, sp2, sp4 and sp5 labeled with HRP were used as conjugates in this sandwich ELISA.

RESULTSThe specificity and sensitivity of the assay were both 100% in detecting anti-HIV of 40 control sera of the second generation panel, higher than indirect ELISA (specificity 90% and sensitivity, 65%, respectively). All of 210 sera from individuals with other diseases were negative for anti-HIV. The consistency rate was 100% when our sandwich ELISA and Abbott HIVAB were used to detect anti-HIV in 90 healthy blood donors and 88 HIV infected individuals.

CONCLUSIONSThe results showed that this sandwich ELISA for detection of anti-HIV is specific, sensitive and convenient, and it is suitable for screening blood donors and detecting HIV infection.

Enzyme-Linked Immunosorbent Assay ; methods ; HIV Antibodies ; blood ; HIV Infections ; blood ; virology ; HIV-1 ; immunology ; HIV-2 ; immunology ; Humans

A safe and effective vaccine against the human immunodeficiency virus type 1 (HIV-1) is expected to have a considerable impact on elimination of acquired immune deficiency syndrome. Despite decades of effort, an effective vaccine against HIV-1 remains elusive. In recent years, the Thai HIV Vaccine Efficacy Trial (known as RV144) showed a reduction in HIV-1 acquisition by 31%, but this agent could not delay disease progression in vaccinated individuals. Clinical analyses of experimental data and experiments in vitro have revealed two main types of immunogen design: induction of broad-spectrum neutralizing antibody (bNAb) and cytotoxic T lymphocyte (CTL) responses. bNAb can prevent or reduce acquisition of infection, and its main immunogens are virus-like particles, natural envelope trimers and stable bNAb epitopes. An effective CTL response can slow-down viral infection, and its main immunogens are "mosaic" vaccines, "conserved immunogens", and the "fitness landscape" of HIV-1 proteins. This review summarizes the strategies as well as progress in the design and testing of HIV-1 immunogens to elicit bNAb and CTL responses.
AIDS Vaccines ; genetics ; immunology ; Animals ; Drug Design ; HIV Antibodies ; immunology ; HIV Infections ; immunology ; prevention & control ; virology ; HIV-1 ; genetics ; immunology ; Humans

BACKGROUND: Many immunochromatography (ICA) kits for anti-human immunodeficiency virus type (HIV) antibody (Ab) have been introduced to improve the accessibility of HIV Ab tests. However, qualified evaluation reports for HIV rapid tests are not enough to validate their performances. Metaanalysis for the performances of the HIV Ab rapid tests was performed in this study. METHODS: PubMed database was searched with combination of search terms, 'human immunodeficiency virus', 'HIV Ab', 'rapid test', 'immunochromatography', 'performance', 'sensitivity', and 'specificity'. Criteria of inclusion were performance studies for HIV ICA kits with serum or EDTA whole blood. Methodological qualities were evaluated with standards for reporting of diagnostic accuracy studies (STARD) checklists by two investigators. Homogeneity among selected studies was evaluated and then pooled sensitivity and specificity were calculated. Positive and negative predictive values were simulated with presumed HIV prevalence in Korea. RESULTS: Twenty-three studies were selected from 12 high-qualified papers with STARD checklists. The performance of 23 studies were found to be heterogeneous (P<0.1) and random effect model was used. Pooled sensitivity was 99.71% (95% CI: 99.45-99.97%) and pooled specificity was 99.27% (95% CI: 98.83-99.70%). With HIV prevalence of 0.03%, positive and negative predictive values were presumed to be 3.936% and 99.999%, respectively. CONCLUSIONS: This meta-analysis for HIV ICA rapid tests showed good performance. In consideration of low positive predictive values of HIV rapid tests, confirmation by enzyme immunoassay or Western blot is still needed. This study would be helpful in evaluating and establishing proper performance guideline for those kits not fully evaluated.
HIV Antibodies/*blood/immunology ; HIV Infections/*diagnosis ; Humans ; Reagent Kits, Diagnostic ; Sensitivity and Specificity

OBJECTIVETo establish and evaluate an Enzyme Immunoassay diagnostic kit combined with anti-HIV1/2 antibody and P24 antigen for shortening the examination window period of HIV infection in HIV laboratory diagnosis.

METHODSThe enzyme-linked reaction plates was coated by anti-HIV P24 monoclonal antibody and HIV 1/2 antigen. Labeling HIV1/2 antigen and anti-HIV P24 polyclonal antibody with horseradish peroxidase, setup an integrated ELISA kit for detecting anti-HIV-1/2 antibody and HIV P24 antigen, and evaluate the specificity and sensitivity of this kit.

RESULTSThe sensitivity of testing P24 antigen was up to 0.2 ng/ml. 78 serum samples of patients with AIDS, 85 serum samples of healthy people were compared with Abbott EIA kit, the coincidence was 100%. 12 051 sera from normal persons and patients were examined, the sensitivity of 100 %and specificity of 99.62 %, respectively.

CONCLUSIONThe anti-HIV1/2 antibody and HIV P24 antigen can be measured at the same time using this EIA kit, while the examination window period of HIV infection is shortened. Thus, the method is suitable for laboratory diagnosis and epidemiological investigation.

Enzyme-Linked Immunosorbent Assay ; HIV Antibodies ; blood ; HIV Core Protein p24 ; blood ; HIV-1 ; immunology ; HIV-2 ; immunology ; Humans ; Reagent Kits, Diagnostic

OBJECTIVETo explore the follow-up visit, outcome and auxiliary diagnosis method on the cases with indeterminate antibody level measured by Western blotting as well as the related biological factors.

METHODSThe cases with indeterminate result were followed up according to the National Guideline for Detection of HIV/AIDS (2009) and samples were collected for HIV antibody detection, p24 antigen and nucleic acid were detected as a supplementary diagnosis at the same time. The samples were also be detected for HBV, HCV, TP, HTLV-I/II, ANA, and AFP, and the results were compared to that of screened positive and confirmed negative cases.

RESULTSA total of 73 were followed up successfully and taken a second HIV test, 25 cases were tested positive and 48 were tested negative for HIV during the follow-up period. For the 25 HIV positive cases, the HIV seroconversion rate was 100.00% at any time point when the interval between the first and returning detection was longer than 1 week. The major Western blotting bands for the cases with indeterminate result were p24 and gp160 and it was different between HIV positive and negative cases in Western blotting band profiles. The consistency and sensitivity of nucleic acid detection were higher than 90.00%, and were higher than that of p24 antigen (69.09% (38/55) and 27.27% (6/22)) (χ(2)(consistency) = 6.875, χ(2)(sensitivity) = 18.893, P < 0.05). The positive rates of ANA and AFP of indeterminate cases excluded from HIV infection were 20.83% (10/28) and 6.25% (3/48) and higher than that of screened positive and confirmed negative cases (0.00%), the difference had statistic significance (χ(2)(ANA) = 19.430, χ(2)(AFP) = 5.520, P < 0.05).

CONCLUSIONIt is critical to get timely diagnosis for the indeterminate cases according to the new national guideline for detection of HIV/AIDS. Nucleic acid detection has higher application value as auxiliary diagnosis for HIV infection than p24 antigen. The increased levels of ANA and AFP may be the factors resulting in the nonspecific indeterminate results.

Antibodies, Antinuclear ; blood ; Female ; Follow-Up Studies ; HIV Antibodies ; blood ; HIV Infections ; diagnosis ; immunology ; Humans ; Male ; alpha-Fetoproteins ; analysis

Serum samples from three populations of Papua New Guinea, where Plasmodium falciparum malaria and human T-lymphotropic virus type 1 (HTLV-1) are coendemic at high prevalence rates, showed statistically significant ELISA co-seropositivity and co-seronegativity. Cross-reactivity was further indicated by the presence of 10 bands ranging from 134 kDa to 18 kDa on immunoblots of electrophoresed whole lysate P. falciparum antigen against serum of HTLV-1 seropositive patients from an area where malaria is not present. Similarly, sera from patients positive for human immunodeficiency virus (HIV) from a non-malarious region produced immunoblot bands ranging from 134 kDa to 33 kDa to the P. falciparum antigen. The HTLV-1 and HIV serum samples yielded a number of immunoblot bands when reacted to an electrophoresed human O type red cell membrane antigen, but those bands had no identity to the cross-reactive bands on the P. falciparum antigen immunoblots. Malaria-positive sera from Papua New Guinean subjects presumed to be uninfected with HIV produced a variety of bands, some of intense prominence, to HIV antigen on diagnostic Western blots. PIP: Serum samples from three populations of Papua New Guinea, where Plasmodium falciparum malaria and human T-lymphotropic virus type 1 (HTLV-1) are coendemic at high prevalence rates, showed statistically significant ELISA co-seropositivity and co-seronegativity. Cross-reactivity was further indicated by the presence of 10 bands ranging from 134 kDa to 18 kDa on immunoblots of electrophoresed whole lysate P. falciparum antigen against serum of HTLV-1 seropositive patients from an area where malaria is not present. Similarly, sera from patients positive for HIV from a nonmalarious region produced immunoblot bands ranging from 134 kDa to 33 kDa to the P. falciparum antigen. The HTLV-1 and HIV serum samples yielded a number of immunoblot bands when reacted to an electrophoresed human O type red cell membrane antigen, but those bands had no identity to the cross-reactive bands on the P. falciparum antigen immunoblots. Malaria-positive sera from Papua New Guinean subjects presumed to be uninfected with HIV produced a variety of bands, some of intense prominence, to HIV antigen on diagnostic Western blots.
Antibodies, Protozoan - immunology ; Enzyme-Linked Immunosorbent Assay ; HIV Seropositivity - immunology ; Papua New Guinea - epidemiology

To obtain the pure and soluble P51 antigen of HIV-1 strain CN54, we transformed the Escherichia. coli strain BL21 codonplus-RIL with recombinant plasmid pTHioHisA51 which carries a gene encoding the Polymerase (Pol) P51 antigen of HIV-1 CN54 formerly, and induced protein expression by IPTG. We purified the recombinant protein with Chelating Sepharose FF-Ni and DEAE-Sepharose FF column chromatography, then renatured the recombinant protein by dialyzation. Purified protein was identified by Western blotting. We labeled and coated antigen P51 in a dual-antigen sandwich system, and tested it with serum samples from HIV-infected individuals. The results showed that P51 was expressed as inclusion body, and represented about 50% of total cellular protein. After purification and renaturation, the purity of P51 was up to 95%. Western blotting and sandwich ELISA demonstrated that recombinant P51 had good anti-HIV antibody specificity and sensitivity. The results suggested that recombinant HIV-1 P51 can be prepared as diagnostic reagent, and provides valuable support for HIV-1 detection and vaccine research.
Escherichia coli ; genetics ; metabolism ; HIV Antibodies ; blood ; immunology ; HIV Infections ; immunology ; virology ; HIV Reverse Transcriptase ; biosynthesis ; genetics ; immunology ; HIV-1 ; classification ; immunology ; Humans ; Protein Renaturation ; Recombinant Proteins ; biosynthesis ; genetics ; immunology ; Sensitivity and Specificity

To identify human monoclonal HIV-l-neutralizing antibodies from an HIV-1 CRF07BC specific phage display antibody library by cell-based screening. 293T cells were transfected by pCH064. 2-Env plas mid and then used to biopan the phage antibody library. The positive phage clones were screened by cell based ELISA and sequenced for the variable region of heavy (VH) and light (VL) chains. The expressed Fabs were purified by Ni(+2) -NTA column and analyzed by SDS-PAGE. The cell- and gp120 protein-based ELISA as well as flow cytometry were used to measure Fab's binding activity. The neutralizing activity of Fabs was assessed by HIV-1 pseudoviruses. After 4-round biopanning, the binding phages to transfected cells were enriched about 650-folds. A total of 28 positive clones were screened out by cell ELISA and sequence analysis identified 5 different Fabs possessing unique VH and VL (2801, 2837, 2863, 2870 and 2920). Interestingly, these Fabs reacted with the Env-transfected 293T cells but not soluble gp120 proteins, suggesting that they might target conformation-dependent epitopes presenting on viral Env complex. We found that three Fabs (2801, 2863, 2870) exhibited potent neutralizing activity against CRF07_BC isolate CH120. 6 with IC50 of 2.24, 0.89 and 3.09 microg/mL respectively, and that 2801 and 2863 cross-neutral ized the subtype B isolate SF162 at IC50 of 0.69 and 3.52 microg/mL respectively. In conclusion, the HIV-1 Env-transfected 293T cells can be used to efficiently enrich and screen the phage antibody library and isolate human monoclonal HIV-1-neutralizing Fabs that target the Env complex-dependent conformational epitopes. Therefore, our studies provide a powerful platform for exploring the mechanism of HIV-1 neu tralizing response and for designing AIDS vaccines.
Antibodies, Monoclonal ; genetics ; immunology ; Antibodies, Neutralizing ; genetics ; immunology ; Enzyme-Linked Immunosorbent Assay ; methods ; HEK293 Cells ; HIV Antibodies ; genetics ; immunology ; HIV Envelope Protein gp120 ; genetics ; immunology ; HIV Infections ; immunology ; virology ; HIV-1 ; genetics ; immunology ; isolation & purification ; Humans ; Immunoglobulin Fab Fragments ; genetics ; immunology ; Neutralization Tests ; Peptide Library ; Transfection

OBJECTIVETo study the incidence and risk factors of HIV and syphilis seroconversion among men who have sex with men (MSM) in Beijing.

METHODSA total of 550 MSM were recruited on the basis of community and followed up after 6 and 12 months in Beijing. Each subject was investigated by only one investigator at one time to collect information on demographics and behaviors. Blood samples were collected to test HIV and syphilis seroconversion. ELISA was used for screening test, west blotting (WB) and Particle agglutination were used for confirmatory test.

RESULTSA total of 550 MSM investigated, among which 4.5% (25/550) were HIV-positive and 29.3% (161/550) were syphilis-positive. For 525 HIV-negative MSM, 87.0% (457/525) retained during the 12-month investigation. Seroincidence for HIV and syphilis were 3.37/100 person-years (95%CI = 1.66 - 5.08) and 9.32/100 person-years (95%CI = 5.87 - 12.77) respectively. HIV seroconversions for those who performed and did not perform rectal douching after homosexual anal intercourse in the past 3 months were 7.11/100 and 0.76/100 person-years respectively. Multivariate Cox regression analysis revealed that rectal douching after homosexual anal intercourse in the past 3 months (HR = 9.23, 95%CI = 2.08 - 40.88) was significantly associated with HIV seroconversion. Syphilis seroconversions for those who met male sex partners in parks, public washrooms or bathhouses in the past 3 months were 41.77/100 and 7.97/100 person-years respectively. Syphilis seroconversions for those who performed and did not perform rectal douching after homosexual anal intercourse in the past 3 months were 16.17/100 and 4.92/100 person-years respectively. In the past 3 months, meeting male sex partners in parks, public washrooms or bathhouses (HR = 4.67, 95%CI = 1.77 - 12.34) and performing rectal douching after homosexual anal intercourse (HR = 3.09, 95%CI = 1.40 - 6.83) were significantly associated with syphilis seroconversion.

CONCLUSIONThe seroconversions of HIV and syphilis during the follow-up visits in this MSM cohort study in Beijing were very serious, and that the associated factors for seroconversions were rectal douching after homosexual anal intercourse and meeting male sex partners in parks, public washrooms or bathhouses.

Adolescent ; Adult ; Antibodies, Bacterial ; blood ; China ; epidemiology ; HIV ; immunology ; HIV Antibodies ; blood ; HIV Infections ; blood ; epidemiology ; HIV Seropositivity ; blood ; epidemiology ; Homosexuality, Male ; Humans ; Incidence ; Male ; Risk Factors ; Sexual Behavior ; Syphilis ; blood ; epidemiology ; Treponema pallidum ; immunology ; Young Adult