Antigens of Human T-Lymphotropic Virus Type III/Lymphadenopathy-Associated Virus

Abstract

Antigens encoded by the gag and env genes of the human T-lymphotropic virus type III/lymphadenopathy associated virus (HTLV-III/LAV) include a p55 gag polyprotein that yields p24 as the major virus core protein, and an env gene polyprotein, gp 160, that produces gp 120, the most immunogenic protein in humans, at the amino terminus. Although its use is limited to research laboratories due to the cost and specialized procedures involved, the analysis of sera by radioimmunoprecipitation and sodium dodecyl sulfate-polyacrylamide gel electrophoresis is the test providing the optimal balance of specificity and sensitivity. Because the gp 120 represents the external virus protein, it would be the most appropriate antigen for vaccine development. Also viruses serologically related to HTLV-III/LAV were detected recently in two species of Old World monkeys. Because about half the healthy African green monkeys appear to have been exposed to simian T-lymphotropic virus type III (STLV-III), a related agent of the species, a characterization of the STLV-III gp 120 and immune response of the host may provide additional information for vaccine development.

Variations in Western blot banding patterns of human T-cell lymphotropic virus type III/lymphadenopathy-associated virus

“…The exact genomic origins of several of the HTLV-III antigens have been clearly established (2). The gag gene codes for a 55-kDa polyprotein (p55) which is cleaved into three smaller proteins: p24 (middle), piS (carboxy terminus), and p17 (amino terminus).…”

Practical diagnostic testing for human immunodeficiency virus

“…It appears that antibodies to the HIV core (gag) protein (p24) and its precursor (p55) occur earliest in infection and tend to decrease or become undetectable with clinical deterioration (39,53,74,76,125). On the other hand, antibodies to the primary envelope (env) gene product (gpl60) and its processed fragments (gpl20) and the transmembrane protein (gp4l) can be detected in nearly all HIV-infected patients regardless of clinical stage (6,37,67). Antibodies to the polymerase gene products (p31, p51, and p66) are also commonly detected.…”

“…Moreover, since nearly all HIV-infected individuals have antibodies to the cell-associated proteins pgl60 and pgl20, the IFA will more readily detect these antibodies. gpl60 and gpl20 are expressed in infected cells, but are generally not present in purified preparations of virus used in EIA kits and in some Western blot procedures (37). However, interpretation of the IFA is more subjective, and uninfected cells may be required for serum absorption.…”

“…In addition, RIPA appears to result in fewer false positives in low-risk blood donors who have isolated bands to core proteins by Western blot (32,45). Therefore, RIPA is probably slightly more sensitive and specific than Western blot and should be considered as a possible supplemental test for serum samples that are indeterminate by Western blot or IFA (32,37). However, RIPA is mainly confined to the research laboratory because it is cumbersome and expensive and requires the maintenance of infected cell lines and handling of radioisotopes.…”

The Expression in Escherichia coli of Sequences Coding for the p18 Protein of Human Immunodeficiency Virus and the Use of the Recombinant Protein in Characterizing a Panel of Monoclonal Antibodies against the Viral p18 Protein

“…In common with other retroviruses the main components of the HIV core are the structural proteins p 18 and p24, which are produced by the proteolytic cleavage of p55, the gag precursor polyprotein (Essex et al, 1985;Montagnier, 1985;Ratner et al, 1985). Ferns et al (1987) recently produced a panel of monoclonal antibodies (MAbs) against the gag proteins p18 and p24 of a British isolate of HIV, CBL-1 (Weiss et al, 1985).…”