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

HIV Infections ; immunology ; HIV-1 ; genetics ; immunology ; Humans ; Mutation ; T-Lymphocytes ; immunology

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

AIDS Vaccines ; administration & dosage ; genetics ; immunology ; Animals ; HIV Infections ; immunology ; prevention & control ; virology ; HIV-1 ; genetics ; immunology ; Humans ; Immunity, Mucosal

BACKGROUNDStudies of highly exposed persistently seronegative (HEPS) individuals may provide valuable information on mechanisms of protection and on vaccine design. Cellular immune responses play a critical role in containing human immunodeficiency virus. However, the cellular immune responses in HEPS individuals have not been thoroughly assessed at the entire viral genome level.

METHODSTen HEPS Chinese with a history of frequent penetrative vaginal intercourse (mean frequency, at least once a week), with some unprotected sexual contact occurring in the weeks or days immediately before enrollment, 25 HIV-1 seropositive individuals, 10 HIV-1-seronegative healthy individuals with low-risk sexual behavior and no history suggestive of exposure to HIV-1 infection were enrolled. HIV-1-specific T cell responses were comprehensively analyzed by an interferon-gamma Elispot assay against 770 overlapping peptides spanning all HIV-1 proteins.

RESULTSHIV-1-specific T-cell responses of interferon-gamma secretion were identified in 3 (30%) out of 10 HEPS individuals; the specific cytotoxic T lymphocytes were targeted at Pol (2/10), Env (2/10), and Tat (1/10). HIV-1-specific T-cell responses of interferon-gamma secretion were identified in 20 (80%) out of 25 seropositive intravenous drug users (IDUs), revealing that all HIV-1 proteins and protein subunits could serve as targets for HIV-1-specific CD8(+) T cell responses with 85% recognizing Gag, 80% recognizing Nef, 75% recognizing Pol, 60% recognizing Env, 55% recognizing Vpu, 45% recognizing Vpr, 20% recognizing Vif, 20% recognizing Tat and 15% recognizing Rev in these seropositive individuals. None of the seronegative healthy individuals gave the positive T-cell responses.

CONCLUSIONSAbout 30% of HEPS Chinese mounted HIV-1 specific T cell immune responses. Cell-mediated immunity against HIV-1 may be developed through non-productive infections.

Adult ; Female ; HIV Seronegativity ; immunology ; HIV-1 ; immunology ; Humans ; Interferon-gamma ; biosynthesis ; Male ; Receptors, CCR5 ; genetics ; T-Lymphocytes, Cytotoxic ; immunology

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

OBJECTIVETo screen aptamers that can bind P24 antigen tightly and specificly, and verify its specificity and affinity.

METHODSPolycarbonate PCR plate was coated with P24 antigen and SELEX technology was used to screen aptamer on the PCR plate. The primary and secondary structure of these aptamers was analyzed by software. Through HRP labeled streptavidin and biotin labeled aptamers, the affinity and specificity of obtained aptamers were verified by ELISA.

RESULTSThe polycarbonate PCR plate could be coated with P24 antigen. Electrophoretic analysis showed the aptamers had been enriched. Sequence aligment analysis showed that these aptamers have consensus sequence and their apatial structure was multiple; ELISA verified that aptamers had high affinity with P24 antigen.

CONCLUSIONA simple method was established for screening aptamers that can bind HIV-1 P24 antigen specificly and tightly.

HIV Core Protein p24 ; analysis ; HIV-1 ; immunology ; Humans ; Polymerase Chain Reaction ; SELEX Aptamer Technique ; methods

Alleles ; Crystallography, X-Ray ; HIV Infections ; HIV-1 ; HLA-B Antigens ; chemistry ; immunology ; Humans

The HIV-1 capsid protein (CA) plays an essential role in viral core assembly and maturation. Proteolytic cleavage at the MA-CA junction of the retroviral gag polyprotein refolds the amino-terminal end of capsid into a beta-helix structure that is stabilized by a salt bridge between the protein's processed amino-terminus and a conserved acidic residue. The refolded capsid aminoterminus then creates a new CA-CA interface, allowing assembly of the mature capsid core. Recently, researches focus on assembly of CA in vitro and development of CA vaccine. CA vaccine will provide widely immune protection because CA is comparatively conserved. Experiments demonstrate that fusing as few as four matrix residues onto the amino-terminus of capsid redirects protein assembly from cylinder to spheres in vitro. Evaluation of immunogenicity showed that immunization with virus-like particles induced both cellular and neutralizing antibody responses. Furthermore, mucosal administration of virus-like particles effectively induced both mucosal and systemic immune responses. These results indicate that virus-like particles consisting of HIV structural proteins are an attractive vaccine platform for eliciting anti-viral immune responses, especially neutralizing antibody responses. The production of antigens for vaccines in plants indicates that plant-based transgenic expression represents a viable means of producing CA vaccine for the development of HIV vaccine and for use in HIV diagnostic procedures and it has the potential as a safe and cost-effective alternative to traditional production systems.
AIDS Vaccines ; immunology ; Capsid ; immunology ; metabolism ; Capsid Proteins ; genetics ; immunology ; metabolism ; HIV-1 ; genetics ; immunology ; metabolism ; Virion ; genetics ; immunology ; metabolism

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