Immunological tolerance to a soluble, partially purified fraction of histocompatibility (H)-2(a) antigen was induced in B10.D2 strain mice. The fraction used was obtained after chromatography on a Sephadex G-150 column. Tolerance of humoral-antibody formation (cytotoxins and hemagglutinins) was observed in mice injected with soluble antigen since birth, but cell-mediated immunity, as measured by skin graft survival, remained intact. Tolerance was shown to be specific for H-2(a) antigens, since treated mice produced a regular humoral-antibody response to H-2(b) antigens. These findings, along with previous observations of the immunogenic and enhancing properties of our partially purified fraction, suggest that the solubilized antigen contains all the major determinants of H-2(a) antigens expressed on lymphoid-cell surfaces.

Animals↗

PubMed1971

Amino-acid sequences of light chains of a rabbit anti-p-azobenzoate antibody.

Half-cystine peptic peptides representing the intrachain disulfide bonds of the light chain from an apparently homogeneous rabbit anti-p-azobenzoate antibody were isolated in good yields after reduction and alkylation with [(14)C]iodoacetate, and their sequences were determined. The sequence of the first 21 amino-terminal residues was also determined. The good yields of these peptides, the fact that no variants of any of them were found, and the cleanness of the amino-terminal sequence determination confirm the high degree of homogeneity of this light-chain preparation. Previous evidence for the homogeneity of the light chain includes the appearance of only a single band upon analysis by disc electrophoresis, a relatively unique amino-acid composition, and a simple tryptic peptide map. The whole antibody shows a homogeneity of the hapten-binding constant. The antigen used in the present work is complex, since the attached hapten groups are in a large variety of environments, particularly since the carrier is a heterogeneous mixture of globulins. The very limited heterogeneity of the antibodies found in this case would appear to depend on the stimulation of only a few of the cells capable of producing antibody against a given hapten, rather than on a structural identity of the environment around each individual hapten group that is located on the antigen molecule.

Amino Acid Sequence↗

PubMed1971

Immunologic enhancement of allogeneic tumor growth with soluble histocompatibility-2 antigens.

Soluble, partially purified, histocompatibility antigens that were obtained from the membranes of A/J spleen cells have been assayed for their capacity to elicit immunologic enhancement of two tumors of A-strain origin: YAA-C1 and Sarcoma I. Crude membrane material and a partially purified, soluble antigen that were contained in a specific fraction, obtained after chromatography on a Sephadex G-150 column, elicited enhancement; this fraction has been shown to contain immunogenic histocompatibility-2(a) antigens as well as alloantigenic specificities that were detected serologically. Another soluble fraction did not induce enhancement; this fraction has been shown to contain antigens other than H-2. Passive enhancement of both tumors was achieved with antisera produced in allogeneic mice that were inoculated with crude membrane material or with a fraction obtained by Sephadex G-150 chromatography. These antisera contained cytotoxic and/or hemagglutinating antibodies. Immunologic enhancement was specific. A readily enhanceable tumor, Py 89, of C57BL origin was not enhanced with anti-H-2(a) antisera. These results suggest strongly that all important H-2(a) transplantation antigenic determinants of spleen cells can be recovered by partial papain digestion and fractionation on a Sephadex G-150 column.

Animals↗

PubMed1971

Amino acid sequences of two mouse immunoglobulin lambda chains.

The amino acid sequences of the lambda chains of two mouse immunoglobulins have been determined. No variations were found between these proteins. The results are compatible with earlier fingerprinting analysis of the two chains, where no differences in the tryptic peptides could be demonstrated. The lack of sequence variations could be the result either of a peculiarly restricted expression of the lambda variable-region genome in the BALB/c myelomas or a small number of germ-line genes involved in the biosynthesis of light chains of the lambda type.

Amino Acid Sequence↗