Myeloma proteins as tumor-specific transplantation antigens.

BALB/c mice immunized with myeloma proteins 315 or 460 made antibodies to the individually specific ("idiotypic") determinants of these proteins and suppressed growth of the corresponding transplanted tumor cells (MOPC-315 or MOPC-460). Stable, variant MOPC-315 tumors that produce only the light chain of protein 315 grew in several of the mice immunized with this protein, probably because the anti-idiotypic immune response selects against those myeloma cells that form the intact myeloma protein.

Establishment of repression by lambdoid phage in catabolite activator protein and adenylate cyclase mutants of Escherichia coli.

Lambdoid phages form clear plaques and show reduced ability to establish immunity in strains of Escherichia coli that lack adenylate cyclase or catabolite activator protein. The absence of the activator protein or cyclic AMP reduces the frequency of lysogenization, but does not prevent steady-state repressor synthesis of a lysogen. Lambda phage mutants able to form turbid plaques on strains that lack catabolite activator protein or adenylate cyclase have been isolated and analyzed.

Autoimmune-like antibodies to the ligand-binding sites of myeloma proteins.

BALB/c mice were immunized with three A-myeloma proteins of BALB/c-2 or BALB/c origin (produced by plasmacytomas MOPC-315, MOPC-460, Adj. PC-22A). Noncross reacting antibodies were formed against Proteins-315 and 460, but the response to Protein-22A was marginal.

Amino acid sequence of the light chain from a mouse myeloma protein with anti-hapten activity: evidence for a third type of light chain.

A tentative amino acid sequence has been determined for the light chain of a mouse A-myeloma (MOPC-315) protein with anti-2,4-dinitrophenyl activity. An unusual amino acid sequence in the carboxyl-terminal 104 residues suggests that the chain represents a new class of immunoglobulin light chain. The "variable" segment of this chain (amino-terminal 110 residues) differs at only eight positions from the corresponding segment of the lambda chain of a mouse M-myeloma (MOPC-104) protein with anti-dextran activity.

Affinity labeling of the heavy and light chains of a myeloma protein with anti-2,4-dinitrophenyl activity.

A mouse myeloma protein with high affinity for 2,4-dinitrophenyl (Dnp) ligands was reacted with the bromoacetyl derivatives of N-Dnp-ethylenediamine and (epsilon)-N-Dnp-L-lysine. Up to 1.4 sites per protein molecule were covalently labeled.

Regulation of repressor expression in lambda.

A new gene in bacteriophage lambda is described. The product of this gene cro prevents expression of immunity and regulates the expression of those genes to the left of the immunity region. cro(-) mutants have been isolated and characterized.

Specificity of the immune response to the 2,4-dinitrophenyl and 2,4,6-trinitrophenyl groups. Ligand binding and fluorescence properties of cross-reacting antibodies.

THE PRINCIPAL RESULTS OF THE PRESENT STUDY ARE: (a) the failure to find an antibody subset that binds a cross-reacting ligand better than the comparable homologue in spite of the use of isolation methods that select for such antibody molecules; (b) the isolation of antibody subsets with virtually indistinguishable average intrinsic association constants for homologous and cross-reacting ligands, but which nevertheless have physical properties (Qmax and relative fluorescence coefficient) that readily distinguish these subsets according to their origin in response to antigenic stimulation with DNP- or with TNP-protein; (c) the demonstration, by precipitin reaction and measurement of association constants for homologous and cross-reacting haptens, of generally greater cross-reactivity among high affinity anti-DNP and anti-TNP antibodies, i.e. low affinity antibodies are generally more discriminating; (d) the selection of anti-DNP and anti-TNP antibody subsets that are distinctive in their ability to show spur formation in gel diffusion reactions with homologous and cross-reacting antigens.