T.L.W. Rothwell

Relationship between eosinophilia and responsiveness to infection with Trichostrongylus colubriformis in sheep.

Lambs with genetically determined increased immunological responsiveness to Trichostrongylus colubriformis (high responders) had more eosinophils in cutaneous reactions to the mitogen phytohaemagglutinin (PHA) both before and during infection compared with those bred for susceptibility (low responders). In contrast, eosinophil numbers in both blood and cutaneous reactions elicited by third-stage T. colubriformis larval antigen were similar in high and low responders before infection. Following vaccination and challenge, high responders had elevated eosinophil numbers in blood and antigen-stimulated skin. In unselected sheep, although eosinophil numbers in cutaneous reactions to PHA were related to responsiveness to a challenge infection with T. colubriformis, there was a closer relationship between blood eosinophil numbers and responsiveness. Infection with T. colubriformis increased eosinophil numbers in cutaneous reactions to PHA and appeared to augment the difference between eosinophil counts in high and low responder sheep. Measurement of the ability to produce eosinophil activating factors, or for eosinophils to respond to such factors might therefore be useful in identifying individual sheep with increased responsiveness to T. colubriformis infection.

Studies of the responses of basophil and eosinophil leucocytes and mast cells to the nematode Trichostrongylus colubriformis: Comparison of cell populations in parasite resistant and susceptible guinea-pigs

Abstract Handlinger J. H. and Rothwell T. L. W. 1981. Studies of the responses of basophil and eosinophil leucocytes and mast cells to the nematode Trichostrongylus colubriformis : comparison of cell populations in parasite resistant and susceptible guinea-pigs. Internationaljournal for Parasitology 11 : 67–70. Basophil and eosinophil leucocytes and mast cells in T. colubriformis resistant and susceptible guinea-pigs were compared. There were significantly more circulating and small intestinal eosinophils in the resistant guinea-pigs. Intestinal eosinophils increased in both groups following infection with T. colubriformis but after 10 days the count in susceptible animals had only reached the pre-infection count in the resistant group. Pre-infection intestinal mast cell counts in the two groups were similar. Mast cell counts in susceptible guinea-pigs did not change during the period of observation but almost doubled within seven days of infection in the resistant animals.

Attempts to probe the antigens and protective immunogens of Trichostrongylus colubriformis in immunoblots with sera from infected and hyperimmune sheep and high- and low-responder guinea pigs

Abstract Comparison of antisera from sheep during primary infection and following vaccination and challenge with Trichostrongylus colubriformis , with antisera obtained following primary infection of high- and low-responder guinea pigs, failed to reveal different antigenic patterns in proteins separated from fourth stage larval extracts by two-dimensional electrophoresis and probed by the immunoblot technique. Generally, serum IgG reacted specifically with worm antigens of mol. wt greater than 94,000, whereas protection against challenge infection was elicited most effectively in the guinea pig by fractions in the 67,000–94,000 range. Most distinct separations of larval proteins by SDS-polyacrylamide gel electrophoresis were obtained by extraction of live larvae and the extracts used within 2–3 days.

Relationship between basophils and eosinophils in cutaneous basophil hypersensitivity reactions in guinea pigs and susceptibility to Trichostrongylus colubriformis infection

Abstract Guinea pigs with genetically determined resistance to primary infection with the nematode parasite Trichostrongylus colubriformis had more basophil and eosinophil leucocytes in cutaneous basophil hypersensitivity (CBH) reactions to keyhole limpet haemocyanin (KLH) than T. colubriformis susceptible guinea pigs. In outbred guinea pigs there was a significant correlation between the number of eosinophils in CBH reactions to KLH after 24 h and resistance to primary infection with T. colubriformis . These results suggest that examination of cutaneous hypersensitivity reactions to non-parasite antigens might be useful in predicting inherent resistance or susceptibility to parasite infection.

Quantitative and qualitative changes in intestinal goblet cells during primary infection of Trichostrongylus colubriformis high and low responder guinea pigs.

Small intestine goblet cell numbers and the composition of their mucus were compared in guinea pigs with genetically determined differences in responsiveness to Trichostrongylus colubriformis infection. Prior to infection, no differences between high responder and low responder animals were detected. However, following primary infection with T. colubriformis, pronounced goblet cell hyperplasia developed and the proportion of sulphomucin in these cells increased. Both changes developed significantly earlier in high responder animals.

Haematological and pathological responses to experimental Trixacarus caviae infection in guinea pigs

Outbred guinea pigs became infected with the mite Trixacarus caviae (Acarina, Sarcoptidae) when introduced into an infected colony. Mite numbers were highest after one month, then fell progressively. Infected guinea pigs developed a neutrophilia, monocytosis, eosinophilia and basophilia. Despite pronounced reactive changes in the superficial lymph nodes, infected guinea pigs developed only a mild dermatitis. In contrast, home bred animals, susceptible to T. caviae acquired many mites and developed a severe chronic dermatitis. Trixacaral manage in guinea pigs offers considerable potential for the study of mite infections in man and animals.

Experimental Haemonchus contortus infections in guinea pigs

Approximately 40% of exsheathed Haemonchus contortus larvae administered to guinea pigs established in the stomach and developed into fourth stage larvae. Most worms were then lost between 5 and 7 days after infection and the guinea pigs were resistant to a second infection. Haemorrhage, oedema and infiltration with inflammatory cells, especially eosinophils, developed in the stomach wall of infected guinea pigs and reactive hyperplastic changes occurred in the gastric lymph node. H. contortus infection of guinea pigs has some potential as a model for study of the pathology, immunology and chemotherapy of gastric nematodiasis.

Expulsion of Trichostrongylus colubriformis by high and low responder guinea-pigs

Guinea-pigs with genetically determined susceptibility to infection with Trichostrongylus colubriformis (or low responders) rejected both primary and secondary infections with this parasite more slowly than resistant animals (high responders). Low responders were not protected with a vaccination procedure which was highly effective in outbred animals. The relatively poor protective immune responses that develop in low responder guinea-pigs are evocative of the responses of the natural host to infection with this parasite and suggest that low responder guinea-pigs have potential for the study of T. colubriformis protective antigens and for the development of adjuvants to enhance antiparasitic effector responses in vaccinated hosts.

The effect of specific immunization or infection with Trichostrongylus colubriformis on production of eosinophil differentiation factors in guinea pigs

The cultivation of bone marrow was used to quantitate the levels of eosinophil differentiation factors (EDF) produced in conditioned medium (CM) by incubation of mesenteric lymph node cells (MLNC) with mitogens or specific antigens from the intestinal nematode parasite, Trichostrongylus colubriformis. In liquid cultures with 20 units ml-1 recombinant murine interleukin-5 (IL-5), bone marrow cells (BMC) from either normal or infected donors contained less than 5% eosinophils and differentiated to greater than 50% eosinophils over 2-3 weeks. Conditioned medium from 3-4 week infected donors produced between 20 and 50% eosinophils when donor MLNC were stimulated with the specific antigen preparation SP3, but macrophages predominated when using CM from MLNC incubated with Concanavalin A (ConA). CM from MLNC of challenged donors incubated with SP3 produced 30-70% eosinophils in BMC assays, with highest levels induced by CM from high responder (HR) donors. Marrow from parasitized or normal donors gave rise to comparable proportions of eosinophils. CM was also produced from LNC of donors given protein or parasite antigens in adjuvant where between 28 and 35% eosinophils were produced in culture. There were no differences between activities attributable to the antigen, but Freunds complete adjuvant induced earlier differentiation of BMC than alum-induced CM. The results confirm that high levels of EDF activity are specifically induced by parasitic infection, and can also be produced by intraperitoneal and subcutaneous inoculation of adjuvanted antigens. Consistent with the greater eosinophilia exhibited by HR guinea pigs to infection with T.colubriformis L3, their MLNC also produced the highest levels of EDF activity.

Effect of Freund's adjuvants on guinea pigs infected with, or vaccinated against, Trichostrongylus colubriformis

Soluble antigens that protected guinea pigs against experimental challenge with Trichostrongylus colubriformis were found to be less effective if injected as emulsions in Freunds adjuvants. This occurred despite the production of higher antibody titres in guinea pigs given emulsified antigen. Investigations of this phenomenon showed that an intraperitoneal injection of Freunds complete adjuvant (FCA) delayed rejection of primary infections and partially abrogated resistance to challenge infection. Administration of FCA/antigen emulsion to infected guinea pigs resulted in a prolonged blood eosinophilia which paralleled the increased longevity of the parasitosis. These findings suggest the need for caution in the selection of adjuvants for vaccination against gastrointestinal nematodes.