Exsheathed infective larvae, fourth stage larvae and adult A. ceylanicum were surface labelled with biotin. The surface proteins were extracted sequentially with Tris buffer saline, sodium dodecyl sulphate and 2-mercaptoethanol then analysed by SDS-PAGE and Western blotting. It was found that A. ceylanicum expresses different surface proteins on each of its three parasitic developmental stages and that these proteins vary in their immunogenicity to the host. Most of the proteins on the surface of exsheathed infective larvae were TBS-soluble and some of these elicited serum antibody responses in infected hamsters. The antibody response to surface antigens recognised by post-primary infection sera was not boosted on reinfection but challenge exposure to larvae induced antibody reactivity to 3 additional L3 polypeptides. The most intense reactivity of post-infection sera was evident with SDS-soluble surface proteins of fourth stage larvae. The post-infection sera showed weaker recognition of the surface antigens of adult worms compared to both larval stages, although the same sera were intensely reactive with adult worm somatic proteins.
The host-parasite relationship of the post-infection tissue resident and migratory stages of Uncinaria stenocephala are areas, which have received very little attention to-date. In the present experiments cellular and serum antibody responses were evaluated in mice infected percutaneously with infective larvae of the nematode. Significant eosinophil infiltration was observed in the skin at the site of infection. The number of these cells increased significantly (p<0.01) and dramatically at the site of the first infection (abdomen) within 24 h of exposure to the second dose of larvae which was administered at a different site (back). A clear IgE response of mice to somatic and surface antigens of L3 was observed. There was no further increase in IgE to the somatic antigen preparations following challenge, but a significantly higher concentration of IgE reactivity to surface antigens was detected 14 days after challenge. A short-lived, IgM, IgG and IgA response to the somatic antigens was also detected.
The antibody responses in resistant (BALB/c) and susceptible, C57BL/10 (BIO) mice to enteral-parenteral and enteral phases of infection with Trichinella spiralis were investigated by ELISA. Generally, IgG and IgA antibodies in both strains of mice remain at low levels during first two weeks of infection. An increase in IgA antibody at mucosal level and in serum was evident in B10 mice during the third week of infection. However, these data indicate genotype dependent IgA response both at mucosal level and in serum. Independently of the route of T. spiralis antigen exposure, B10 mice produced high level of IgA antibody in the second and third weeks of infection. Immunoblotting was used to analyse the components of the two antigen (AgL1 and AgAd) preparations recognized by IgG and IgA from sera, or IgA from intestinal lumen samples (ILS) of infected mice. In both strains of mice the antigen recognition profiles of the two analysed antigens were different for specific IgA in ILS and IgG or IgA in sera. Characteristically, in B10 mice infected by enteral-parenteral route specific IgA response to AgL1 was aggregated in low molecular weight (33-38 kDa) components, whilst enteral infection stimulated IgA responses at the mucosal level by higher molecular weight components (62-67 kDa).
To assess the humoral immunological responses at the IgG subclass level in yersiniosis specific antibody responses against lipopolysac-charide of Yersinia enterocolitica O3 (LPS) and Yersinia Yop proteins were analyzed by ELISA. Thirty five patients with arthritis and forty nine patients with uncomplicated yersiniosis were included in the study. Analysis of the IgG subclass responses to the LPS revealed that the subclass distribution for both groups of patients was IgG2>IgG1>IgG3. The concentration of IgG4 was below detection level. The predominant antibody responses to Yop proteins were IgG1 >IgG3>IgG2>IgG4 but the frequency of detection of particular IgG subclass antibodies were dependent on the age of patients. Generally, the frequency of occurrence of IgG2 antibodies for Yop proteins of Yersinia together increased with age reaching its peak among individuals aged above 40 years. On the other hand, IgG1 for Yop proteins and IgG3 for Y. enterocolitica LPS were diagnosed more often in serum samples obtained from children than from adults. We also found significantly higher frequency of IgG4 to Yop proteins of Y. enterocolitica in men than in women.
Bile antibody responses of naturally infected cattle to surface and ES protein antigens of adult D. dendriticum were analysed. Freshly isolated and carefully purified flukes were surface labelled with NHS- biotin or biotin hydrazide (BH) and extracted using Tris-buffered saline. Biotinylated surface proteins or glycoproteins were then isolated by streptavidin affinity chromatography. ES products were obtained during 24 h incubation of undamaged worms at 37 °C in Tyrode’s salts solution enriched with antibiotics. Bile samples were collected at slaughter from cattle harbouring 120-280 lancet flukes. The fluke antigens inducing bile antibody responses were analysed by SDS-PAGE, Western blot and ELISA techniques. Bile from non-infected cattle precipitated none of the surface proteins and one polypeptide out of ES products. One to 6 polypeptides were found in immunocomplexes formed by individual bile samples of infected cattle and surface proteins while immunocomplexes formed by bile and surface extracts of flukes labelled with BH contained 2-5 fluke glycoproteins. An average of 3 polypeptides were recognised in ES products. In ELISA tests 38-67% out of 150 samples reacted with ES antigens while 70% possessed antibodies against surface proteins and 92% against surface glycoproteins. It is suggested that the surface and ES antigens may be of particular importance in the host-parasite relationship.