Immunomodulation by peptide analogs of retroviral envelope protein

• Published in: Peptides (New York, N.Y. : 1980) N.Y. : 1980), 2003-07, Vol.24 (7), p.979-985
• Main Authors: Mehrotra, Shikhar, Mishra, Kamla P, Yadav, Virendra S, Bhattacharya, Madhushree, Pandey, Deepa, Haq, Wahajul, Singh, Vijay K
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Biological and medical sciences; Cell Line; Cytokines; Cytotoxicity Tests, Immunologic; Fundamental and applied biological sciences. Psychology; Humans; Immune System - drug effects; Immunomodulators; Interleukin-2 - metabolism; K562 Cells - immunology; Killer Cells, Natural - drug effects; Killer Cells, Natural - immunology; Leukocytes, Mononuclear - drug effects; Leukocytes, Mononuclear - immunology; Leukocytes, Mononuclear - metabolism; Lipopolysaccharides - pharmacology; Lymphocyte Culture Test, Mixed; Macrophages - drug effects; Macrophages - immunology; Mice; Mixed lymphocyte reaction; Molecular Sequence Data; Nitric oxide; Nitric Oxide - analysis; Nitric Oxide - metabolism; Peptides - chemical synthesis; Peptides - chemistry; Peptides - pharmacology; Phytohemagglutinins - pharmacology; Retroviral peptide; Retroviridae Proteins - chemistry; Spectrometry, Mass, Fast Atom Bombardment; Tumor Necrosis Factor-alpha - metabolism; Vertebrates: endocrinology; Viral Envelope Proteins - chemistry
• ISSN: 0196-9781; 1873-5169
• DOI: 10.1016/S0196-9781(03)00189-X

The mechanism by which retroviral proteins exert their immunosuppressive influence has remained enigmatic. Early studies have demonstrated that retroviral infection suppresses cellular and humoral immune responses. A hydrophilic 26 amino acid region of the otherwise hydrophobic transmembrane envelope protein of murine and feline leukemia viruses, p15E, is conserved among the transmembrane envelope proteins of numerous animal retroviruses (e.g. murine, feline, bovine and simian) as well as in human T-cell leukemia virus, and to a lesser extent, in human immunodeficiency virus (HIV). We evaluated the immunomodulatory properties of various synthetic retroviral envelope peptides synthesized as overlapping fragments to this conserved sequence. We report that two small peptides inhibit human mixed lymphocyte reaction (MLR), interleukin-2 (IL-2) and tumor necrosis factor (TNF-α) production. These peptides did not affect human natural killer (NK) cell cytotoxicity in vitro, and nitric oxide (NO) production in mouse macrophage cells, RAW264.7. Our observations suggests immunomodulatory potential of two retroviral peptide analogs.