Identification of membrane antigen C33 recognized by monoclonal antibodies inhibitory to human T-cell leukemia virus type 1 (HTLV-1)-induced syncytium formation: altered glycosylation of C33 antigen in HTLV-1-positive T cells.
We isolated four monoclonal antibodies (MAbs), M38, M101, M104, and C33, which were capable of inhibiting syncytium formation induced in a human T-cell line, MOLT-4-#8, by coculture with human T-cell leukemia virus type 1 (HTLV-1)-positive human T-cell lines. The MAbs had, however, no inhibitory activity on syncytium formation induced in a human osteosarcoma line, HOS, by HTLV-1-positive T-cell lines. They also did not inhibit syncytium formation induced in MOLT-4-#8 by human immunodeficiency virus type 1-positive MOLT-4. All MAbs reacted with various human cell lines of lymphoid and nonlymphoid origins, including HTLV-1-positive T-cell lines. Furthermore, they all reacted with a murine A9 clone containing human chromosome 11 fragment q23-pter. Two MAbs, M104 and C33, immunoprecipitated a membrane antigen with the same molecular size. The antigen (henceforth called C33 antigen) was about 40 to 55 kDa in HTLV-1-negative Jurkat, CEM, MOLT-4, and normal peripheral blood CD4-positive human T cells and about 40 to 75 kDa in HTLV-1-positive C91/PL, TCL-Kan, MT-2, and in fresh HTLV-1-transformed CD4-positive human T-cell lines. Pulse-chase experiments revealed that C33 antigen was synthesized as a 35-kDa precursor that was then processed to 41 to 50 kDa in MOLT-4 and to 44 to 70 kDa in C91/PL. In the presence of tunicamycin, a 28-kDa protein was synthesized. The conversion from 35 kDa to 41 to 50 kDa in MOLT-4 and to 44 to 70 kDa in C91/PL was inhibited by monensin. Treatment with N-glycanase alone, but not with sialidase and O-glycanase in combination, completely removed the sugar moiety of C33 antigen from both HTLV-1-negative Jurkat and HTLV-1-positive C91/PL. Therefore, C33 antigen has only N-linked carbohydrates, the modification of which appears to be substantially altered in the presence of the HTLV-1 genome.
Fukudome
K
K
Shionogi Institute for Medical Science, Osaka, Japan.
Furuse
M
M
Imai
T
T
Nishimura
M
M
Takagi
S
S
Hinuma
Y
Y
Yoshie
O
O
D000911:Antibodies, Monoclonal / Q000276:immunology*; D015703:Antigens, CD; D000954:Antigens, Surface / Q000737:chemistry*; D002459:Cell Fusion; D002880:Chromosomes, Human, Pair 11; D006031:Glycosylation; D015368:Human T-lymphotropic virus 1 / Q000472:pathogenicity*; D006801:Humans; D051861:Kangai-1 Protein; D008562:Membrane Glycoproteins / Q000737:chemistry / Q000502:physiology*; D008970:Molecular Weight; D011499:Protein Processing, Post-Translational; D011518:Proto-Oncogene Proteins; D011991:Receptors, Virus / Q000737:chemistry / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology / Q000382:microbiology*; D014407:Tumor Cells, Cultured; D014760:Viral Fusion Proteins / Q000502:physiology*
D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000954:Antigens, Surface; C497688:CD82 protein, human; D051861:Kangai-1 Protein; D008562:Membrane Glycoproteins; D011518:Proto-Oncogene Proteins; D011991:Receptors, Virus; D014760:Viral Fusion Proteins