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Specificity of T and B lymphocytes for myeloma protein 315

1977; Wiley; Volume: 7; Issue: 7 Linguagem: Inglês

10.1002/eji.1830070705

1521-4141

T. JØRGENSEN, Kristian Hannestad,

Monoclonal and Polyclonal Antibodies Research

Abstract The antibody response of BALB/c mice directed against the idiotype of the BALB/c myeloma protein MOPC 315 (M315) is T cell‐dependent. The specificity of helper T cells for M31 5 was investigated. Helper cells were primed with M31 5, M315 affinity‐labeled with N α ‐bromoacetyl‐N ε ‐2,4‐dinitrophenyl‐L‐lysine, M315 L‐chain and H‐chain the M315 Fv fragment, myeloma protein MOPC 460 and monoclonal human kappa and lambda chains. The primed cells were transferred together with (4‐hydroxy‐5‐iodo‐3‐nitrophenyl(acetyl)) (NIP)‐primed B cells to 500 R‐irradiated recipient syngeneic BALB/c mice which were challenged with NIP s M315. The anti‐NIP antibody responses were augmented by helpers primed with all derivatives and subunits of M315. This effect disappeared almost completely when the helper cells were treated with anti‐Thy‐1,2 and C prior to transfer. Priming with M460 induced weak and inconsistent helper effects, which opens the possibility that some of the helper cells may recognize nonidiotypic determinants on M315. The strong and consistent helper effect induced by free M315 L‐chain (L‐31 5)‐primed cells was not due to dissociation of NIP‐L‐315 from intact NIP 5 M315 used for challenge, because L‐315‐primed T cells also augmented the antibody response against the idiotype of M315 which is only expressed on associated (H+L) chain pairs. In contrast, BALB/c antibodies elicited by free L‐315 were specific for a determinant which was present on free L‐chains but which was not or only minimally accessible on the complete M315. The data indicate that the helper cells recognize determinants which are separate from the ligand binding site of M315 and which are accessible on both the complete M315 7 S subunit and its isolated chains. In contrast, B cells stimulated by free L‐315 recognize determinants which are hidden on associated (H+L) chains. Moreover, the associated (V L +V H ) domains of M31 5 Fv fragment, which lacks C domains are immunogenic for T helper cells.