title: Complement-dependent cytotoxic antibodies to human T lymphotropic virus type I (HTLV-I)-infected cells in the sera of HTLV-I-infected individuals.
abstract: To investigate whether HTLV-I induces the development of complement-dependent cytotoxic antibodies in humans, sera of asymptomatic HTLV-I carriers and of patients suffering from tropical spastic paraparesis/HTLV-I-associated myelopathy (TSP/HAM) or adult T cell leukaemia (ATL) were used in a cytotoxicity assay against a panel of target cells. This panel included uninfected cell lines (CEM, Jurkat, Molt and H9), cell lines chronically infected with HTLV-I (MT2, MT4, C9IPL and HUT102), as well as lines H36 (H9 infected with HTLV-I), H9-IIIB (H9 infected with HIVms) and H9-MN (H9 infected with HIMVMN). HTLV-I+ sera induced lysis of H36 and of lines expressing HTLV-I antigens in the presence of rabbit complement, but did not lyse cells in presence of human complement. The HTLV-I+ sera also failed to lyse the HTLV-I- lines and H9 cells, suggesting that lysis was specific for HTLV-I. H36 cell lysis was prevented by IgG depletion of the sera and by dialysis of rabbit complement against EGTA or EDTA. Rabbit complement-dependent cytotoxic antibodies were present in the sera of 14/14 HTLV-I-infected individuals; the highest titres were predominantly found in the sera of the TSP/HAM patients. Such antibodies were also detected in 5/5 individuals coinfected with HIV-1 and HTLV-I, although no cytotoxic antibody could be found against HIV-infected cells. Vice versa, sera of HIV-1-infected individuals did not exert a lytic effect in the presence of complement (of human or rabbit origin) against HIV-1- or HTLV-I-infected cells. Incubation of the sera of four HTLV-I-infected patients with HTLV-I env-specific synthetic peptides demonstrated that some of the complement-dependent cytotoxic antibodies recognized epitopes located on gp46 between amino acids 190 and 209. There is no correlation of rabbit complement-dependent cytotoxic HTLV-I antibodies with the development of disease.
authors.affiliation: Unité de Recherche sur les Hépatites, INSERM U271, Lyon, France.
authors.forename: H
authors.initials: H
authors.lastname: Plotnicky-Gilquin
authors.forename: A
authors.initials: A
authors.lastname: Afani
authors.forename: J C
authors.initials: JC
authors.lastname: Vernant
authors.forename: C
authors.initials: C
authors.lastname: Desgranges
mesh_terms: D000914:Antibodies, Viral / Q000096:biosynthesis / Q000097:blood*; D000920:Antibody-Dependent Cell Cytotoxicity; D000961:Antilymphocyte Serum / Q000097:blood*; D002460:Cell Line; D003165:Complement System Proteins / Q000502:physiology*; D015490:HTLV-I Infections / Q000097:blood* / Q000209:etiology / Q000276:immunology*; D015368:Human T-lymphotropic virus 1 / Q000276:immunology*; D006801:Humans; D015459:Leukemia-Lymphoma, Adult T-Cell / Q000209:etiology; D015493:Paraparesis, Tropical Spastic / Q000209:etiology
chemical_list: D000914:Antibodies, Viral; D000961:Antilymphocyte Serum; D003165:Complement System Proteins