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Query: UMLS:C0019693 (HIV)
 170,526 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The induction of CD4+ T-helper (Th) cell responses is likely to be an important requirement of vaccine candidates designed to prevent or moderate human immunodeficiency virus-1 (HIV-1) infection. We have investigated the ability of hybrid Ty virus-like particles carrying the V3 loop region of the HIV-1 IIIB envelope gp120 (V3:Ty-VLP) to elicit V3-specific proliferative responses. Significant proliferation in response to stimulation in vitro with homologous IIIB V3 peptide was observed following immunization of mice with V3:Ty-VLP either as an aluminium hydroxide precipitate or without adjuvant. Responses to MN V3 peptide were also observed in certain mouse haplotypes. To assess the effect of presenting the V3 loop in this particulate form, we compared the responses induced by V3:Ty-VLP with those obtained with two non-particulate immunogens, recombinant gp120 (rgp120) and V3 peptide conjugated to albumin. V3-specific responses to V3 peptide in vitro were reproducibly higher following immunization with V3:Ty-VLP than with either rgp120 or V3-albumin coagulate (V3-alb). The data indicate that immunization with the V3 loop as a hybrid Ty-VLP results in enhanced proliferative responses to V3 peptide and recognition of rgp120 in vitro. Some cross-reactivity of Th cells for V3 sequences from different isolates was also observed.
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PMID:Enhanced proliferative cellular responses to HIV-1 V3 peptide and gp120 following immunization with V3:Ty virus-like particles. 136 83

A sodium hydroxide extract from cacao husk inhibited the cytopathic effect of human immunodeficiency virus type 1 (HIV-1) against HTLV-1-transformed T-cell lines MT-2 and MT-4. It also inhibited syncytium formation between HIV-infected and uninfected lymphoblastoid T-cell line, MOLT-4. The anti-HIV activity was concentrated by membrane filter fractionation to a fraction with molecular weight of 100-300 KDa. Anti-HIV activity of the extract was attributable to interference with the virus adsorption, rather than to inhibition of the virus replication after adsorption.
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PMID:Effect of cacao husk extract on human immunodeficiency virus infection. 136 48

T helper cell antigenic and immunogenic determinants of the nef protein were investigated in the rat and chimpanzee models using recombinant nef protein and five synthetic peptides selected according to their amphipathic and alpha-helicity properties. The nef protein was shown to be immunogenic with both Freund's or aluminium hydroxide adjuvants. After immunization with the nef protein the 45-69 peptide was the most antigenic in rat and monkey models. In contrast, the 98-112 peptide, that required a carrier protein to induce in vitro rat T cell recall proliferation, was able to restimulate monkey T cells in the absence of a carrier. The amino acid sequence carrying the antigenic activity of the 45-69 peptide was further investigated by synthesizing short peptides overlapping this region. The antigenic sequence was precisely located in the middle of the peptide (region 50-59). This sequence was antigenic only when N alpha-acetylated. Circular dichroism analysis of the 45-69 peptide and the in vitro activity of the N-terminus group indicate in this case the involvement of the alpha-helical propensity for antigen presentation. However, the shorter sequence 50-64, able to induce a T cell reactivity, was determined as a beta-pleated sheet structure in aqueous solution. The 45-69 peptide was not only antigenic but also immunogenic and behaved in vivo as a functional T helper cell epitope. Indeed, the priming with the peptide or the transfer of peptide specific T cells to a naive recipient, followed by immunization with the nef protein, enhanced the subsequent antibody response to the nef protein. Together, these data indicate that the 45-69 peptide appears as a candidate for the in vivo elicitation of T cell immunity to the HIV-1 nef regulatory protein.
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PMID:T helper cell epitopes of the human immunodeficiency virus (HIV-1) nef protein in rats and chimpanzees. 137 67

A Gag protein segment of human immunodeficiency virus 1 (HIV-1) has been fused to a C terminally truncated core antigen of hepatitis B virus (HBcAg) using an E. coli expression system. Fusion of 90 amino acids of HIV-1 Gag protein to HBcAg still allowed the formation of capsids presenting on their surface epitopes of HIV-1 core protein, whereas fusion of 317, 189, or 100 amino acids of Gag prevented self-assembly of chimeric particles. Mice immunized with recombinant particles emulsified with Freund's complete adjuvant (CFA) or aluminium hydroxide developed high anti-HBcAg titers. However, anti-HIVp24 antibodies were detected only in mice inoculated with immunogen emulsified with CFA.
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PMID:Immunogenicity of recombinant core particles of hepatitis B virus containing epitopes of human immunodeficiency virus 1 core antigen. 138 12

Vaccines made by inactivating pathogenic microorganisms have been dramatically successful in controlling diseases in humans and animals. Despite their successes, they have a major disadvantage in that several inoculations are required for them to be effective. To overcome this problem, a commercial inactivated vaccine preparation against tickborne encephalitis was combined with human growth hormone (HGH). This formulation produced complete protection in a murine model with only one dose of vaccine, apparently by binding hormone and antigen to an insoluble matrix containing aluminium hydroxide. Thus it is postulated that when virus-specific lymphocytes are attracted to the site of injection, the hormone is at a high local concentration and stimulates the clonal expansion of antigen-specific T cells. The development of genetically engineered HGH now gives unlimited supplies of hormone, potentially resulting in an increase in efficacy of a wide variety of vaccines, especially those needing prolonged immunization schedules such as those being developed to combat human immunodeficiency virus infection.
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PMID:Adjuvant effect of human growth hormone with an inactivated flavivirus vaccine. 205 4

The aim of the present study was to determine the effect of polymethylmethacrylate (PMMA) nanoparticles as adjuvants for an HIV-2 whole-virus vaccine in mice. The data clearly revealed that PMMA nanoparticles induced 10-100-fold higher antibody titres than aluminium hydroxide or an aqueous vaccine control preparation as measured by enzyme-linked immunosorbent assay. Moreover, the high antibody titres obtained with PMMA as adjuvant appeared to be stable for between 10 and 20 weeks after immunization. In contrast, the titres of the control preparations, fluid or aluminium hydroxide formulations, decreased after 10 weeks.
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PMID:High antibody titres in mice with polymethylmethacrylate nanoparticles as adjuvant for HIV vaccines. 205 85

The major envelope glycoprotein, gp120, of human immunodeficiency virus type 1 (HIV-1) was purified from a Chinese hamster ovary cell line transfected with a truncated form of the HIV-1 env gene. The recombinant glycoprotein (rgp120) was formulated with aluminum hydroxide adjuvant and was used to immunize chimpanzees. The recombinant preparation was effective in eliciting cellular and humoral immunity as well as immunologic memory. Anti-rgp 120 antibodies reacted with authentic viral gp120 in immunological blot assays and were able to neutralize HIV-1 infectivity in vitro. Sera from the rgp120-immunized animals were able to neutralize HIV-1 pseudotypes of vesicular stomatitis virus prepared from the IIIB isolate, from which the gene encoding rgp120 was derived, as well as two heterologous isolates, ARV-2 and RF. The immune response elicited against the rgp120 was not effective in preventing viral infection after intravenous challenge with HIV-1. The implications of these results on HIV-1 vaccine development are discussed.
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PMID:Human immunodeficiency virus type 1 challenge of chimpanzees immunized with recombinant envelope glycoprotein gp120. 245 98

A number of minimised hammerhead ribozymes (minizymes) which lack stem II have been kinetically characterised. These minizymes display optimal cleavage activity at temperatures around 37 degrees C. The cleavage reactions of the minizymes are first order in hydroxide ion concentration up to around pH 9.3 above which the cleavage rate constants decline rapidly. The reactions show a biphasic dependence on magnesium-ion concentration; one of the interactions has an apparent dissociation constant of around 20 mM while the other appears to be very weak, showing no sign of saturation at 200 mM MgCl2. The minizymes are significantly less active than comparable, full-size ribozymes when cleaving short substrates. However, at a particular site in a transcribed TAT gene from HIV-1, minizymes are more effective than ribozymes.
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PMID:In vitro activity of minimised hammerhead ribozymes. 747 37

The development of peptide-based vaccines that elicit antibody (Ab) and cellular immune responses has been hampered by the lack of highly immunogenic formulations. In this study, we compared the induction of Ab and cytotoxic T-lymphocyte (CTL) responses to a peptide derived from the V3 loop of HIV-1 gp120 (P18 and its cysteine-glycine derivative (CG-P18)) when incorporated into liposomes with lipid A (LA) or mixed with aluminum hydroxide. P18-specific CTL were only observed with liposomes with LA. P18-specific Ab responses were found with liposomes containing CG-P18 but not P18. Increased surface expression of the former, resulted in enhancement of the Ab response without loss of CTL induction. Thus, the manner in which a peptide is localized can influence the outcome of the response induced by highly immunogenic liposome formulations.
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PMID:Antibody and cytotoxic T-lymphocyte responses to a single liposome-associated peptide antigen. 749 19

Cationic phthalocyanines with either aluminum or silicon as the central metal were evaluated for their ability to inactivate viruses in red blood cell concentrates (RBCC) photodynamically. In addition, the virucidal potential of a substituted anionic phthalocyanine, aluminum dibenzodisulfophthalocyanine hydroxide (A1N2SB2POH) was evaluated and compared with that of the much studied anionic aluminum tetrasulfophthalocyanine hydroxide (A1PcS4OH). Based on the rate of inactivation of the lipid-enveloped vesicular stomatitis virus (VSV), the virucidal potential of these phthalocyanines was: HOSiPcOSi(CH3)2(CH2)3N+(CH3)3I- (Pc 5) = SiPc[OSi(CH3)2-(CH2)3N+(CH3)3I-]2 (Pc 6) > A1PcOSi(CH3)2(CH2)3N+(CH3)2(CH2)11CH3I- (Pc 21) = A1N2SB2POH = A1PcS4 > HOSiPc[OSi(CH3)2(CH2)3N+(CH3)2(CH2)11CH3I-]2 (Pc 14) > A1PcOSi(CH3)2(CH2)3N+(CH3)3I- (Pc 2). Phthalocyanine ligand 14 and Pc 21 are new phthalocyanines, made by quaternizing known amino analogues. Compared to VSV, the rate of inactivation of Sindbis virus (another model lipid-enveloped virus) was identical when treated in red blood cells (RBC) with Pc 5 and slightly higher when treated with Pc 6 and A1PcS4OH. Treatment of RBCC containing cell-free human immunodeficiency virus (HIV-1) with Pc 5 or A1PcS4OH required 15 min of irradiation to inactivate (> 5 log10 reduction) the virus. The extent of HIV-1 inactivation with A1N2SB2POH was 3.7 log10 after 60 min of red light exposure. The RBC integrity after photosensitization was measured by the ability of the cells to bind to plates coated with poly-L-lysine, (which reflects the retention of the RBC surface negative charges) and hemolysis of the cells over a 7 day storage period.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:New phthalocyanines for photodynamic virus inactivation in red blood cell concentrates. 793 15


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