Ju ST, Strack P, Dorf ME. Production and immunoselection of IgM-IgA hybridomas: preparing immunoglobulins with dual binding specificity.
Mol Immunol 1989;
26:283-92. [PMID:
2495437 DOI:
10.1016/0161-5890(89)90082-5]
[Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Fusion between the thioguanine resistant myeloma cell line MOPC-315 [which produces alpha, lambda-2 antibodies specific to the 2,4-dinitrophenyl (DNP) hapten] and a long term in vivo maintained hybridoma 6100.15 [which produces mu, lambda-1 antibodies specific to the 4-hydroxy-3-nitrophenyl acetyl (NP) hapten] resulted in the generation of 12 hybridomas. These hybridomas secrete a mixed family of immunoglobulins (Ig) that bind both DNP and NP and express both IgM and IgA serological determinants. Affinity purified molecules from NP, DNP, anti-mu, or anti-alpha immunosorbents react with both anti-mu and anti-alpha antisera, suggesting that these Ig represent IgM-IgA hybrid molecules. This conclusion was supported by idiotypic analyses. To determine the roles of individual immunoglobulin chains in determining antibody specificity this IgM-IgA hybridoma was used for immunoselection. Following lysis with specific anti-mu and anti-idiotype antibodies, an alpha+, mu- variant clone (A12) was identified, which secreted Ig that binds DNP but not NP. The DNP binding proteins were shown to express alpha, lambda-1 and lambda-2 chains. In contrast, the Ig which lack DNP binding activity only expressed alpha and lambda-1 determinants. The combined results demonstrate that the lambda-1 chain from 6100.15 hybridoma cannot replace lambda-2 of MOPC-315 for DNP binding activity. These data imply that these closely related lambda chains carry sites critical for antigen binding activity. An IgM-IgA hybridoma variant (MA2) which secretes Ig that binds to NP and DNP and expresses mu, alpha and lambda-2 chains was also characterized. This molecule lacked a lambda-1 chain. To determine if the Ig prepared with heterologous mu and lambda-2 chains had NP binding activity required immunoselection of a fourth clone (M2). M2 secretes homogeneous Ig bearing only mu and lambda-2 chains. In contrast to either parental Ig, the M2 antibody molecules express dual binding activity to both NP and DNP. Thus, critical amino acid substitutions in the MOPC-315 lambda-2 sequence are required for DNA binding specificity.
Collapse