The envelope (env) and structural (gag) gene products of human T-cell leukemia (lymphotropic) virus type III were identified by immunoaffinity chromatography, immunoprecipitation, and two-dimensional oligopeptide mapping methods. The env gene specifies a glycosylated polypeptide with a molecular weight of 160,000 (gp160) that is processed to gp120 and smaller gene products. The gag gene specifies two polypeptides of 70,000 and 55,000 molecular weight (p70 and p55), both of which contain p24, the major structural protein of the mature virion. The techniques in this study can be used to define the extent of variability of the env gene product among different virus isolates and may identify the nature and patterns of the humoral immune response that lead to an immunologically protected state.

https://science.sciencemag.org/content/sci/228/4699/593.full.pdf

Characterization of envelope and core structural gene products of HTLV-III with sera from AIDS patients

INFECTION of macaques with simian immunodeficiency virus (SIV)1,2 and human immunodeficiency virus type 2 (HIV-2) 3,4 are useful models for studies of immunotherapy and vaccination against HIV as well as for testing of antiviral drugs. Vaccine research showing protective immunity in immunized monkeys4–10 has indicated that it will be possible to develop a vaccine for prevention of human HIV infection, although many hurdles remain. The design of an HIV vaccine would be helped if the basis of the protective immunity could be elucidated. Passive immune prophylaxis offers a means to determine the relative role of antibodies in protection against infection. We have studied whether a transfer of antibodies can prevent HIV-2 and SIVsm (SIV of sooty mangabey origin) infection in cynomolgus monkeys. Sera with high antibody titres were collected, heat-treated and injected into naive animals 6 h before challenge with 10–100 monkey-infectious doses of live homologous virus. All control animals treated with normal monkey serum (n = 6) or no serum (n = 39) became infected by the challenge virus, whereas five out of seven animals pretreated with antibody-containing serum at a dose of 9 ml kg−1 resisted infection. Thus passively transferred antibodies can protect against a low-dose lentivirus challenge in a nonhuman primate.

Prevention of HIV-2 and SIVsm infection by passive immunization in cynomolgus monkeys.

Monoclonal antibodies against a thymus cell differentiation antigen (Thy-1.1) were effective in the therapy of a transplanted mouse leukemia. Passive immunization resulted in high titers of cytotoxic antibody in the serum of treated mice and the suppression of metastatic tumor cells. The tumor-suppressive effects of the monoclonal antibodies were amplified by the administration of exogenous complement. This combined antibody and complement therapy resulted in the cure of leukemia in a significant proportion of the treated animals.

https://science.sciencemag.org/content/sci/207/4426/68.full.pdf

Mouse leukemia: therapy with monoclonal antibodies against a thymus differentiation antigen.

Two glycopolypeptides with molecular weights 160,000 and 120,000 (gp120) are regularly recognized by human immunodeficiency virus (HIV)-specific antisera in lysates of cells persistently infected with HIV. In the present study, gp120 was characterized as the major envelope glycopolypeptide of HIV. Gp120 was identified as the external viral glycoprotein by radiosequencing and by its presence in purified virus. However gp120 was predominantly shed as a soluble protein into the culture fluid. Furthermore gp120 was precipitated by sera from horses infected with equine infectious anaemia virus (EIAV), but not by sera from uninfected animals. This may indicate conserved epitopes common to the envelopes of HIV and EIAV.

Shedding and interspecies type sero-reactivity of the envelope glycopolypeptide gp120 of the human immunodeficiency virus.

The envelope gene of the helper-independent, highly leukemogenic virus Friend murine leukemia virus was sequenced by using a molecular clone of a Friend murine leukemia provirus. The deduced amino acid sequences of the envelope proteins gp70 and p15env were homologous to the sequences of Moloney murine leukemia virus (86%) and Akv (76%). However, a stretch of about 40 amino acid residues near the middle of gp70 was dissimilar in Friend and Moloney murine leukemia viruses and Akv. In this type-specific region the gp70s of all three viruses contained more than 30% proline residues, giving this sequence a very rigid conformation. We suggest that this rigid and highly variable region of gp70 participates in infection by recognition of cell surface receptors and, in addition, might contribute to the different oncogenic spectra of murine leukemia viruses.

Nucleotide sequence of the envelope gene of Friend murine leukemia virus.

Properties of mouse leukemia viruses. IX. Active and passive immunization of mice against Friend leukemia with isolated viral GP71 glycoprotein and its corresponding antiserum.

[Evidence for the existence of different antigenic determinants of the interspecies type in mammalian RNA-C-type tumor viruses. Comparative serological studies on viruses of various animal species including a virus suggested to be of human origin (author's transl)].

Mammalian C-type oncorna viruses. Relationships between structural virus and cell surface antigens and their possible significance in immunological defense mechanisms.

Moennig

Papers

Properties of mouse leukemia viruses. IX. Active and passive immunization of mice against Friend leukemia with isolated viral GP71 glycoprotein and its corresponding antiserum.

[Evidence for the existence of different antigenic determinants of the interspecies type in mammalian RNA-C-type tumor viruses. Comparative serological studies on viruses of various animal species including a virus suggested to be of human origin (author's transl)].

Mammalian C-type oncorna viruses. Relationships between structural virus and cell surface antigens and their possible significance in immunological defense mechanisms.