Antibodies directed against diagnostic Mr 31 000 polypeptide(s) of adult Schistosoma mansoni were already formed in mice during prepatency. In contrast, repeated immunization of mice with homogenates of adult schistosomes failed to elicit antibodies detectable in immunoblots in the Mr 31 000 region. Therefore, spleen cells of infected mice were used to produce hybridoma lines. The “miniblot technique” was developed in order to detect in hybridoma supernatants antibodies against schistosome Mr 31 000 components. Electrophoretically separated total S. mansoni proteins were transferred onto nitrocellulose, and the position of the Mr 31 000 components was determined with polyclonal antisera and immunoblotting. Pieces of about 3 square mm of nitrocellulose bearing the diagnostic proteins were incubated with about 100 μ1 of hybridoma supernatant in microtitre plates and subsequently probed with peroxidase-conjugated antibody to mouse IgG. This screening technique identified hybridomas secreting antibody to the relevant S. mansoni antigens. It is applicable to other defined parasit antigens, which are, however, not available in biochemically purified form. The monoclonal antibodies produced against the proteins with diagnostic potential reacted with antigens localized in the schistosome gut.

Onchocerca gutturosa and O. lienalis inflections in British cattle were studied by examination of cattle post-mortem originating from North Wales and Cheshire (north west England). In 463 adult animals, the microfilarial (mf) prevalence was 28·5%. In 95·3% of the inflected animals, gravid worms could not be found at either the ligamentum nuchae or the gastro-splenic omentum. Dermal mf at the head were identified as O. gutturosa on the basis of their highly significant assocation with the presence of gravid O. gutturosa at the ligamentum nuchae, which were found in only 3·2% of cattle. Mfs were isolated from different skin sites and from adult worms and a minimum of 10 mfs from each isolate were examined for width and acid phosphatase (AP) staining pattern. The width of O. gutturosa dermal mf was <4 μm (4 isolations), narrower than of putative O. lienalis mf isolated from umbilical skin of cattle without evidence of O. gutturosa, which were in 20/22 isolations >4 μm wide. The dermal mf were also distinguished on the basis of different AP staining patterns which, for each species, correlated closely with that of hatched intrauterine mf from their respective adult female worms. Based on the criteria of morphology and AP staining patterns the mf species prevalences in the survey population were estimated as O. lienalis 24·1% and O. gutturosa 2·2%, with a further 2·2% of cattle inflected with both species. The results indicate that the predilection site of adult O. lienalis is not the gastro-splenic omentum. In North Wales, the distribution of the two species was different; O. lienalis was widely distributed in all cattle rearing areas both lowland and upland, whereas O. gutturosa was largely restricted to valleys close to major rivers.

A series of experiments was carried out using adult outbred Polish race rabbits of both sexes infected, during spring or autumn. with 10 000 larvae of Obeliscoides cuniculi, either fresh or stored at 4°C. Extracts of mucosal proteins and bile were collected at postmortem 6 or 12 weeks after infection. Antibody levels were determined in antisera. bile and stomach mucosa by haemagglutination and precipitation tests. Local antibody respones were demonstrated in the stomach and bile, and reactions were obtained with the tissue fluids by haemagglutination and precipitation tests with worm antigens and ES products. Additionally, some specific immunological response was observed in the circulation during the primary infection. These results suggest a clear-cut relationship between increased levels of these antibodies and either larval inhibition or worm expulsion during O. cuniculi infections.

The innate resistance of the unnatural rat host to the mouse tapeworm Hymenolepis nana is cortisone sensitive but thymus independent. When congenitally athymic nude rats were orally given eggs, cysticercoids, or adult worms of H. nana, no lumenal adults were established except when they were treated with cortisone acetate during the expected lumenal development. The effect of cortisone to promote adult maturation in the rats was compared in nude and normal rats given eggs of H. nana. The fecundity of the worm (assessed by the fresh worm biomass and the number of infective eggs produced) was much higher in cortisone-treated nude rats than in cotrisone-trated norml rats. When the nude rats recostituted with thymocytes were given eggs and treated with cortisone, the fecundity of H. nana dropped to the same level as in cortisone-treated normal rats. It is strongly suggested that the unnatural rat host has thymus-independent cortisone sensitive resistance to an intial infection (which is the main component of the innate resistance and blocks the lumenal establishment of this parasite) and thymus-dependent resistance (which suppresses the established worm' fecudity and may be ascribed to acquired resistance to the ongoing infection).

The surface antigens of oncosphere, cysticercoid, adult scolex and adult strobila (other than scolex) of Hymenolepis nana differ critically from one another. When the oncosphere of H. nana undergoes differentiation and development into the mature tapeworm, the infected mouse first produces anti-oncosphere antibody, followed by anti-cysticercoid, anti-adult scolex and finally anti-strobila (other than scolex region) antibodies of IgG, IgM and IgA isotypes as detected by indirect immunofluorescent antibody test. The parasite changed its surface antigens throughout its differentiation and maturation, and all developmental stages were recognized by the infected mouse host. However, there appeared no further changes in surface antigens during aging after maturation. The antibody responses were always delayed compared with the differentiation and maturation of the parasite.

Five lambs were each sensitized with 400 metacercariae of Fasciola gigantica irradiated at 3 kr gammarays. Eight weeks later, they were each challenged together with 5 controls with 500 non-irradiated metacercariae. Eight weeks later, all of the animals were necropsied and the worm burdens determined. The lambs which received the sensitizing infections had 80% less worms than the controls. The sensitized lambs also showed less hepatic damage compared with the controls as indicated by lower levels of the serum enzyme glutamate dehydrogenase. The blood indices showed insigicant reductions in the sensitized lambs whereas marked reductions were found in the erythrocytes, packed cell volume and haemoglobin values of the challenge controls. Bilirubinaemia was also evident in this latter group.

The oxidative metabolism of Gastrothylax crumenifer mitochondrial fractions was assayed polarographically at 30°C in the presence of various substrates. Succinate was most readily oxidized, malate and pyruvate were oxidized at subsantially lower retes. The spcific inhibitors such as malonate, KCN, NaN3, oxaloacetate, salicylhydroxamic acid and oligomycin effectively affected the mitochondrial oxygen consumption. The results indicate the presence of oxidative phosphorylation and cytochrome systems. Mitochondrial ATPase was found to be active.

Gastrothylax crumenifer haemoglobin was isolated, purified, chromatographed, and its molecular weight determined on a calibrated Sephadex G–100 column as well as by sodium dodecyl sulphate by the former and 16 500 by the latter method. The oxygen affinity of the pigment (P50O2) was found to be 6·1 mm Hg at pH 7·4.

Hamsters experimentally infected with Opisthorchis viverrini had significant depression of the antibody response to sheep red blood cells. The depression was more severe with prolonged infections. Lymphoproliferative response to phytohaemagglutinin stimulation was also depressed when compared with uninfected controls. The immunodepression in these animals was abolished by anthelmintic treatment, suggesting that the immunodepressive effect is reversible and is associated with active infection.

A marked strain variation in eosinophilia following oral infection with Toxocara canis eggs was observed in mice. Mutual radiation chimeras between high and low responder mice in terms of eosinophilia were made and compared with the respective donor and recipient for eosinophilia after the infection. As a result, the degree and time course of eosinophilia in chimeric mice were similar to those in donors. The result suggested that genes which regulate inheritance of the trait, marked eosinophilia in T. canis-infected mice, might be expressed in bone marrow derived cells.

The growth of Philophthalmus gralli from jordan was studied experimentally by inoculating 10 excysted metacercariae around the right eye of 47 day-old chicks. The growth rate was slow in the first three days during which flukes did not exceed 0·30 mm long. Then growth become rapid reaching 2·70 mm long on day 24. This was followed by a low growth rate during which the flukes grew from 2·70 mm to 2·90 mm on day 40. The flukes started to appear in the left eye on the day 12 post-inoculation of metacercariae in the development of P.gralli from Jordan was the same as of other species of Philophthalmus. However, a sixth stage, post-maturation stage, is suggested in addition to the 5 developmental stages of Philophthalmus. The ratio of the transverse diameter of the ovary to that of testes in the post-maturation stage was 1:1·1–1:1·2.

Adult males of Schistosoma mansoni were preincubated in 5-hydroxtryptamine (5HT) and processed through the glyoxylic acid fluorescence technique to visualize 5HT-containing neural elements. 5HT flourescence was seen as a series of cross-sectional rings beginning behind the ventral sucker toward the tail end. The rings were connected by two lateral nerve cords running longitudinally along the whole lenght of the worms.

The initial pathway of skin penetrating larvae of Strongyloides ratti inside the host is not systemic and could well involve local components of the lymphatic system. The experiments described were an attempt to detect an effect on immunity depending on whether larvae of a challenge infection were committed to a pathway through heavily primed or lightly primed lymph nodes. Female rats were immunised by subcutaneous injection into the right forearm of 1000 heat killed, or 1000 live, third stage larvae of S. ratti. Animals given living parasites were placed on a diet containing 0·1 or 0·2% thiabendazole 48h or 36h after ifection. Challenge infections of <100 larvae (‘exact’ doses) were applied on day 21 to either the right or left flank and, similarly, to controls that had received the anthelmintic but not the priming infection. Heat killed parasites elicited no response at all. Priming with live larvae stimulated a significant immunity (16% and 37% depression in 2 experiments), but there was no difference between rats whose challenge was on the same side as the priming dose and those which had the contralateral treatment. The significance of these results to theories of pathfinding in general, and to practical immunology, is discussed.

Mongolian gerbils were infected with either a benzimidazole-susceptible or a benzimidazole-resistant strain of Trichostrongylus colubriformis larvae. The comparative pathogensis of both strains of T. colubriformis was investigated for 50 days post-infection. The gerbils infected with the drug-susceptible strain of the parasite showed lower survival rates, reduced body weights, higher parasite egg output and higher worm burdens than animals intected with the drug-resistant stram of parasite. There was also evidence of an enhanced hypoalbuminaemia and a more marked gastrointestinal plasma leak in the gerbils infected with the drug-susceptible strain of patasite. Scanning electron microscope examination of the small intestine showed signs of villus atriphy in both groups of ingected grebils.