Biomedical subjects
Publications and source records attributed to S Yahiro.
Both enantiomers of trans-5-benzyloxy-4-methoxy- (BMOx) and trans-4,5-dimethoxy-2-oxazolidinones (DMOx), which are readily accessible from simple 2-oxazolone heterocycles, represent good candidates for a new class of chiral synthons for use in the preparation of optically pure alpha-amino aldehydes and alpha-amino acids, respectively.
Immunoglobulin allotypes and complement (C) are known to be related to susceptibility to infection. Because bovine IgG2 is important in resistance to pyogenic infections and because its two allotypes, IgG2a and IgG2b, differ in sequence in the CH1, hinge, CH2, and CH3 regions, we tested the ability of these allotypes to initiate the bovine C cascade. Bovine IgG2a and IgG2b were standardized according to specific anti guinea pig red blood cell (GPRBC) ELISA activity using anti IgG2 reagents shown essentially unbiased for allotype. Complement activating activity of the allotypes was quantitated in a GPRBC lysis assay. With this system, IgG2b consistently had more than twice the activity in bovine C mediated lysis as compared with IgG2a. The fact that both EDTA and EGTA/Mg almost completely inhibited C mediated lysis of GPRBCs indicated that lysis was due to the classical pathway. Since antibody usually activates C by the classical pathway, this supports the supposition that activation was by the IgG2-GPRBC complexes. Flexibility analyses showed that IgG2b had a more rigid hinge than IgG2a, perhaps partially explaining the greater efficiency of IgG2b in C activation. Other mechanisms may include differences in glycosylation and in the amino acid at position 332. The difference in ability to activate C may mean that animals of the IgG2a allotype could be more susceptible to infection with extracellular pyogenic pathogens which are killed by C or by phagocytes after opsonization with IgG2 and C.
We have cloned the cDNA of TBA-1, the Nematode polyprotein allergen (NPA) of Toxocara canis and found it to be most similar to ABA-1, the Ascaris NPA, on the basis of amino acid sequence. We could study the antigenic properties of an E-coli synthesized fusion protein prepared with the cloned gene since no glycosylation site was expected from the deduced amino acid sequence. Although no IgE responses to TBA-1 were detected, recombinant TBA-1 was differently recognized by serum IgG antibodies when the recombinant TBA-1 was directly adsorbed vs when immobilized via a streptavidin linkage on polystyrene microtitre wells. One group of sera recognized TBA-1 directly immobilized while the second only recognized TBA-1 immobilized via streptavidin linkage. The former were from rodents immunized with a Toxocara sp. adult worm extract while the latter were obtained from rodents infected with T. canis larva or immunized with a Anisakis simplex L3 larval extract. These observations suggest that the two in vivo forms of TBA-1 are expressed, but during different stages of the parasite's life cycle.