Preparation and characterization of a monoclonal anti-T helper factor antibody.

Sprague-Dawley rats were immunized by injection of antigen B-specific T helper factor THF) eluted from Sepharose-antigen D adsorbents. Rat spleen cells from animals immunized with THF were fused with a BALB/c tumour cell (P3x63-Ag8.653) to prepare monoclonal anti-THF antibodies. The hybrids produced were screened for anti-THF antibodies by an enzyme-linked immunoassay (ELISA), and we shall describe the characteristics of one of the hybrid (hybridoma 6-2.2 anti-THF) antibodies produced. (i) The monoclonal hybrid 6-2.2 anti-THF antibody blocks water-soluble timothy extract-induced proliferation of timothy-specific T helper cells when these cells were preincubated with an excess of the anti-THF hybrid 6-2.2 antibody; (ii) incubation of timothy-specific T helper or T suppressor cells with an optimal dose of anti-THF 6-2.2 antibody induces significant levels of [3H]-thymidine incorporation in the absence of antigen; (iii) it binds specifically to the idiotypic determinant expressed on THFk, THFd, TSFk, and antigen B-specific IgE in an ELISA; and (iv) it has no effect upon spleen cells from mice primed with ovalbumin or Ascaris suum antigens. In addition, the monoclonal anti-THF 6-2.2 antibody cultured with normal spleen cells in mini-Marbrook chambers induced significant levels of antigen B-specific T suppressor cells. These studies indicate that the monoclonal anti-THF 6-2.2 antibody has anti-idiotypic antibody properties.