ABSTRACT
A method for the measurement of neutralising antibodies (nab) directed against SIVmac or HIV-2 was developed. The assay is based on antigen detection using a non-commercial enzyme-linked immunosorbent assay (ELISA). Studies were carried out to determine the influence of the test conditions on the nab titre. The sensitivity of the assay depended mainly on the virus dose and the length of incubation of the serum-virus-mixture. Prolongation of the culture time from 9 to 11 days increased the validity of the results. Applying this neutralisation assay on sequential serum samples from SIV mac- or HIV-2ben-infected macaques, a considerable variation was found in nab titres between individual animals. Whereas after infection with SIVmac, in vitro-neutralisation seems to correlate with protection against disease, and the lower pathogenity of HIV-2ben in macaques compared with SIVmac is not due to the differences in nab titres.
Subject(s)
Antibodies, Viral/immunology , Enzyme-Linked Immunosorbent Assay/methods , HIV-2/immunology , Simian Immunodeficiency Virus/immunology , Acquired Immunodeficiency Syndrome/blood , Acquired Immunodeficiency Syndrome/immunology , Acquired Immunodeficiency Syndrome/virology , Animals , Antibodies, Viral/blood , Antigens, Viral/immunology , HIV-2/isolation & purification , Macaca , Neutralization Tests , Simian Acquired Immunodeficiency Syndrome/blood , Simian Acquired Immunodeficiency Syndrome/immunology , Simian Acquired Immunodeficiency Syndrome/virology , Simian Immunodeficiency Virus/isolation & purificationABSTRACT
The purpose of this study was to characterize antigenic determinants on structural polypeptides of human immunodeficiency virus type 2 (HIV-2ben). Therefore, three HIV-2-specific monoclonal antibodies (mAbs) against the p24 core protein (gag) and one mAb against the gp130 envelope glycoprotein (env) were produced. In addition to p24 the anti-core mAbs recognized the primary translation product of the viral gag gene p55 and an intermediate cleavage product p41. Core mAbs cross-reacted with another HIV-2 isolate (HIV-2rod), and several simian immunodeficiency viruses (SIVagm TYO7 and SIVmac), but not with SIVmnd and the HIV-1 isolates investigated (HIV-1han and HIV-1lai). The env mAb cross-reacted with HIV-2rod and SIVmac but not with SIVagm, SIVmnd or HIV-1. In competition assays and with epitope mapping possible binding sites for the mAbs were identified. The processing of HIV-2 core proteins is compared in retrovirus-infected T cell lines and during the expression by recombinant vaccinia virus. Finally, the mAb XIV DC10 which recognized a highly conserved epitope could be useful for an assay to detect HIV-1 and HIV-2 simultaneously. II D8 is the first mAb raised against HIV-2 env glycoprotein.
Subject(s)
Antibodies, Monoclonal/biosynthesis , Gene Products, env/immunology , HIV Core Protein p24/immunology , HIV-2/immunology , Amino Acid Sequence , Animals , Antibody Specificity/immunology , Blotting, Western , Cross Reactions , Enzyme-Linked Immunosorbent Assay , Epitopes/immunology , HIV Antibodies/immunology , HIV Antigens/immunology , HIV-1/immunology , Mice , Mice, Inbred BALB C , Molecular Sequence Data , Simian Immunodeficiency Virus/immunology , env Gene Products, Human Immunodeficiency VirusABSTRACT
Five monoclonal antibodies (MAbs) were raised against the gag proteins of simian immunodeficiency virus (SIV) from African green monkey (SIVagmTYO-7). Two MAbs reacted with the matrix protein p17 and the other three with the core protein p24. Studies on the cross-reactivity of the MAbs revealed that the anti-p24 MAbs detected an epitope shared by the viruses belonging to the human immunodeficiency virus type 2 (HIV-2)/SIVmac group and SIVagmTYO-7 and SIVagmTYO-5. The anti-p17 MAbs recognized an epitope present on all these viruses and on SIVagmTYO-1, HIV-1 and SIVmnd. This finding demonstrates for the first time that the matrix protein, p17 or p18, respectively, of all nine HIV and SIV isolates tested in this study expresses at least one conserved immunogenic epitope recognized serologically. By using synthetic peptides, this epitope was identified at the N terminus of p17. Furthermore, this epitope was analysed by multiple sequence alignments of the peptide with homologous sequences of HIV and SIV p17.