Vaccination of sheep against haemonchosis with H11, a gut membrane-derived protective antigen from the adult parasite: prevention of the periparturient rise and colostral transfer of protective immunity.

Pregnant ewes were immunised with a fraction highly enriched in the membrane glycoprotein antigen H11, isolated from the intestinal brush border of adult Haemonchus contortus. Immunity induced by immunisation was able to abolish almost completely (98-99%) the worm egg output from pregnant ewes challenged with ca. 10,000 infective larvae of H. contortus during the last trimester. Furthermore, lambs born and reared on vaccinated ewes had substantial antibody levels to H11 derived from maternal transfer. This antibody conferred moderate protection against a bolus challenge of ca. 3000 infective larvae of H. contortus in 5-week-old lambs.

Effect of recombinant porcine somatotropin and monoclonal antibody directed to ovine somatotrophic hormone on nitrogen retention and immune parameters in pigs.

Single and combined effects of administration and withdrawal of recombinant porcine somatotropin (rpST) and an enhancing murine antiovine growth hormone monoclonal antibody (OA15) on nitrogen retention, and serological and immunological measurements in pigs were examined in a placebo-controlled experiment. Thirty-six barrows were allotted to one of four treatments: control, rpST, OA15, and OA15+rpST. The trial phase was four balance periods: a preperiod, two periods of treatment, and a postperiod. Weight- and nitrogen gain were higher for the rpST group by 13% (P < .01) and 15% (P < .001), for the OA15 group by 8% (P < .05) and 9% (P < .05), and for the OA15+rpST group by 25% (P < .001) and 20% (P < .001), respectively compared with the control group. During the postperiod, weight gain of the OA15- and the OA15+rpST group was 23% (P < .001) and 22% (P < .001) lower than that of the control group. Nitrogen gain during the postperiod was decreased by 19% (P < .01) for the OA15 group compared with the control group. Single or combined administration of rpST or OA15 did not affect (P > .10) cellular constituents in the blood of all groups during the periods of observation. Animals treated solely with rpST mounted a humoral immune response directed to rpST. This anti-rpST antibody response was, however, decreased (P < .01) in barrows treated with rpST and OA15 simultaneously. Also, a slight anti-rpST antibody response was noticed in barrows solely treated with OA15.(ABSTRACT TRUNCATED AT 250 WORDS)

Identification of enhancer sequences 3' of the rabbit Ig kappa L chain loci.

The rabbit is useful for studies of Ig L chain gene expression because of a great disparity in expression of two isotypic forms of the kappa L chain. Normally, K1 is expressed at high levels and K2 is almost silent; expression of K2 increases in mutant or experimentally allotype-suppressed animals. The reasons for the preferential utilization of the K1 isotype have not been fully elucidated. We were interested in looking for second enhancers 3' of the C kappa genes because the absence of a 3' enhancer in the K2 locus could explain the preferential utilization of the K1 isotype. However, we found a strong region of enhancer activity about 7 kb downstream of the C kappa 2 gene. Sequences in this region are highly conserved between rabbit, man, and mouse. There also appears to be a homologous 3' enhancer region in the rabbit K1 locus. We also confirmed earlier reports that the rabbit K1 intron enhancer is inactive in transient transfections into mouse B cells but find that the same construct has low but significant activity in a human B cell line. In a comparable construct the K2 intron enhancer is without activity suggesting possible differential activity of the intronic enhancers.

Mapping of the duplicated rabbit immunoglobulin kappa light chain locus.

The rabbit has two isotypic forms of the immunoglobulin kappa light chain, K1 and K2, which probably arose by duplication. In the normal rabbit, only traces of K2 light chains are produced. However, K2 levels are elevated in allotype-suppressed rabbits and in the Basilea strain which does not produce K1 because of a K1 mRNA splice site mutation. Previous cloning and sequencing showed that each isotype has its own set of J kappa genes but it was not known whether the two isotypes utilize shared or separate sets of V kappa genes. In addition, although genetic linkage of allotypes associated with the K1 and K2 genes has been demonstrated, physical linkage had not been previously demonstrated by overlapping cosmid or phage clones. We used pulsed field and transverse alternating field electrophoresis to obtain megabase maps and to estimate the size of the duplication of the rabbit kappa light chain locus. We found that the two C kappa genes are about 1 megabase apart. One explanation for the poor expression of K2, could be great physical distance from V kappa genes. However, we found that there are V kappa, J kappa and C kappa 2 genes within a approximately 105-kb fragment. Thus, physical distance of V kappa from C kappa 2 may not be the basis for poor K2 expression.

Genetic analyses of restriction fragment length polymorphisms using high molecular weight DNA from sperm or lymphocytes embedded in agarose.

A simple and efficient method for determining restriction fragment length polymorphism types on large numbers of individuals using small samples of peripheral blood or sperm cells is described. Whole cells embedded in low gelling/melting temperature agarose were treated with a series of enzyme, detergent, and washing steps to release high molecular weight DNA that was then digested with standard restriction enzymes such as EcoRI and PstI, electrophoresed, blotted, and probed as in normal Southern analyses. The technique should be readily adaptable to any application requiring DNA from small numbers of cells for Southern analyses or pulsed field gel electrophoresis.

Linked genetic markers of the rabbit kappa light chain are not linked to the Tcr beta chain genes.

In order to investigate linkage, we used serum allotypes of the two rabbit C kappa isotypes and restriction fragment length polymorphisms (RFLPs) of the genes for V kappa, C kappa, and T-cell receptor C beta. The inheritance of these genetic markers was studied through backcross and F2 matings. Southern analysis and hybridization of genomic DNA with a C kappa probe detected a 5 kb Pst I fragment linked to expression of the K2bas1 allotype and the presence of the kappa 1bbas gene and a 6.6 kb Pst I fragment linked to the expression of the K1b9 allotype, the presence of the kappa 2bas2 gene and lack of expression of the K2bas1 allotype. A V kappa probe detected a 1.3 kb Eco RI fragment linked to the presence of the kappa 1bbas gene and expression of the K2bas1 allotype. In contrast, the 9 or 14 kb Eco RI RFLP (C beta a or C beta b) detected with a Tcr beta chain probe segregated independently from C kappa allotypes and RFLPs. It has previously been found that C kappa and C beta are also unlinked in man, whereas in the mouse they are linked at a distance of approximately 8 centimorgans.

The idiotypy of auto anti-allotype antibody induced in immunoglobulin allotype suppressed rabbits.

Rabbit anti-rabbit idiotype antibody was raised to both clonally heterogeneous and restricted auto anti-b6 antibodies induced in b6 allotype-suppressed (b6)/(b6) homozygous and b4/(b6) heterozygous rabbits. In every case the anti-idiotypic antibodies were specific only for the inducing antibody as shown by direct binding solid-phase RIA. Anti-idiotypes directed to the same antibody preparation had a similar but not identical specificity. It was demonstrated by IEF that the same idiotype specificity (spectrotype) was present throughout the anti-b6 response in individual rabbits.

Escape from b locus allotype suppression in the rabbit is mediated by IgM molecules bearing an allotope-restricted variant of kappa light chain.

Rabbits homozygous for b6 at the kappa light chain b locus were suppressed for the expression of the b6 allotype and then induced to produce auto anti-b6 antibody. Rabbits which subsequently escaped suppression produced auto antibody with restricted allotype specificity. Escape from allotype suppression was mediated by IgM bearing a kappa chain variant with a restricted number of b6 allotopes and having a diminished interaction with auto anti-b6 antibodies from the same and other rabbits escaping b6 suppression. This suggested that there were allelic variants or subpopulations of the b6 light chain which were under independent regulation of expression, clearly influenced by the specificity of auto anti-allotype antibody. Since escape from suppression was mediated by IgM it is proposed that a normal pathway of B cell differentiation occurs during recovery from suppression.

Presence of kappa 2 light chain in normal rabbits and as induced auto anti-allotype antibody in kappa 1 light chain suppressed subjects.

Using an antiserum raised in b(bas)/b(bas)-suppressed rabbits to kappa 2 light chain we have shown that the kappa 2 light chain is an isotype of kappa 1, present in the majority of, if not all, rabbits. It probably exists in at least 2 allelic forms. It is capable of producing a functional antibody molecule (auto anti-b6) and compensates for the absence of kappa 1 light chain in homozygous b6-suppressed rabbits.