Quantitative variations in L chain types in guinea pig antihapten antibodies

Guinea pig immunoglobulin light chain isotypes. I. Separation of kappa and lambda chains and the identification of three isotypes of the lambda chain constant homology region

The separation of intact kappa chain and two fragments comprising lambda (lambda) chain from immunoglobulin light chain pools isolated from strain 13 guinea pigs is achieved by cyanogen bromide digestion and gel filtration before and after reductive clevage of disulfide bonds. The smaller lambda chain fragment derives from the original carboxyl-terminus of lambda chain. The partial sequence of component tryptic and thermolytic peptides of this thirty-nine residue fragment allowed its complete sequence to be deduced. Three isotypic forms of this lambda chain constant region fragment, distinguished by four residue positions showing alternative amino acids, are found expressed by guinea pigs. Each of these three isotypes is more homologous to the other two than to lambda chains of any other species. The distribution of amino acid substitutions differentiating these isotypes further supports the view that lambda chain isotypes arose in guinea pigs, and in several other species, independently by gene duplication.

The sheep immune response. Variation of anti-hapten and anti-carrier antibodies in the 1 and 2 immunoglobulin fractions

The results obtained in the quantification of γ₁ and γ₂ anti-hapten (DNP) and anti-carrier (HGG) antibodies obtained weekly during 50 weeks and proceeding from a group of three Merino sheep immunized with DNP—HGG, are described.

The primary and secondary response and the antibody variations in weekly repeated stimulations were studied.

The anti-DNP and anti-HGG total antibodies have similar variations. γ₁ and γ₂ anti-DNP and anti-HGG antibodies do not show differences in the primary response nor in weekly repeated stimulations.

In the secondary response, a high increase of γ₁ with loss of γ₂ is observed. After a certain time γ₁ decreases and γ₂ increases.

Antigen-binding thymus-derived lymphocytes. II. Nature of the immunoglobulin determinants

Thymus-derived `rosette'-forming lymphocytes which have been separated from other SRBC-sensitive cells by means of cotton wool columns were examined for the presence of immunoglobulin. This was carried out by inhibition of rosette formation by anti-immunoglobulin sera. Inhibition was effected by a number of anti-IgM sera shown to contain antibodies with specificities directed towards the `hinge' region of the μ chain. No other heavy chain specific antisera were inhibitory.

The ratio of rosette inhibition by anti-κ and anti-λ light chain sera varied during the course of the response to SRBC, the latter inhibiting by 89 per cent 3 days post-immunization.

The immune response in the hamster. 3. Selective induction of concomitant antibody formation and unresponsiveness in the 7S 1 - and 7S 2 -globulins with soluble hen egg albumin

Synthesis of antibody to hen egg albumin (HEA) was restricted to one of the 7S immunoglobulins (7Sγ₁-globulin) when hamsters were inoculated with soluble HEA (HEA—saline). This selective induction occurred regardless of the amount of HEA—saline injected (0.001–5.0 mg) or the route of inoculation. In contrast, HEA in Freund's adjuvants induced synthesis of anti-HEA in both the 7Sγ₁- and 7Sγ₂-globulins, even when as little as 0.1 μg of HEA was used. Repeated inoculations of hamsters with HEA—saline increased or maintained 7Sγ₁-antibody, but did not induce anti-HEA synthesis in the 7Sγ₂-globulins. The results of cell transfer experiments indicated that cells from HEA—saline treated hamsters were primed to synthesize 7Sγ₁ anti-HEA and were specifically unresponsive for 7Sγ₂ anti-HEA synthesis. Selective induction of antibody production and unresponsiveness, concomitantly, within different immunoglobulin classes suggests that different antibody induction mechanisms are utilized by these two immunoglobulin classes.

Amino acid sequence restriction in rabbit antibody light chains

Light chains were obtained from IgG rabbit antibodies to the group-specific carbohydrates of groups A and C streptococci. An analysis of the amino acid alternatives which exist at the first three positions of the N-terminus in both light-chain preparations shows a marked restriction in amino acid sequence heterogeneity when compared with preimmune light chains. Both of these related, but immunologically distinct, antigenic determinants select the same uncommon subpopulation of rabbit light chains.

Antihapten antibody specificity and L chain type

Two types of light polypeptide chain (kappa and lambda) are present in guinea pig immunoglobulins. The ratios of K/L molecules in anti-hapten antibodies differ sometimes markedly from that found in normal serum. Anti-DNP antibodies and anti-pipsyl antibodies have, respectively, a higher and a lower than normal K/L ratio. The possibility that the L chain type affects the range of configurations which the antibody-combining site may assume was investigated. Fractional precipitation of anti-DNP antibodies from serum of guinea pigs immunized with DNP(44)-BSA was performed using limiting amounts of antigen. Antibody fractions were purified from each precipitate, their affinities for epsilon-DNP-L-lysine measured by fluorescence quenching (K(0)) and the K/L ratio estimated by precipitation with specific antisera. Increasing concentrations of L molecules were found in fractions with decreasing K(0). In other experiments, fractional precipitation and purification of antibodies which cross-react with DNP was performed in serum of animals immunized with pipsyl-BGG. The K/L ratio in antibodies isolated from these fractions was much higher than in fractions which do not cross-react with DNP. These results show that K molecules are better adapted to react with the DNP hapten than L molecules. The K/L ratio in anti-DNP antibody was shown to increase in the course of immunization, at the same time that the K(0) is increasing. This rise in K(0) is markedly delayed when larger doses of antigen are employed.

Presence of two types of L polypeptide chains in guinea pig 7S immunoglobulins

Guinea pig 7S immunoglobulins (gamma(1) and gamma(2)) consist of two groups of molecules (K and L) bearing different types of L chains (kappa and lambda). Approximately one-third of the molecules in normal guinea pig gamma(2)-globulin bear the lambda- type of L chains, and all or most of the others bear kappa-chains. kappa- and lambda-chains have similar molecular weights.