Changes in intestinal regulatory peptides in mice infected with the rat tapeworm, Hymenolepis diminuta

Changes in intestinal regulatory peptides in mice infected with the rat tapeworm, Hymenolepis diminuta

49 CHANGES IN INTESTINAL TAPEWORM, HYMENOLEPIS REGULATORY DIMINUTA PEPTIDES IN MICE INFECTED WITH THE RAT D.M. McKAYI D.W. HALTON' C.F. JOHNSTON* ...

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49 CHANGES IN INTESTINAL TAPEWORM, HYMENOLEPIS

REGULATORY DIMINUTA

PEPTIDES

IN MICE INFECTED WITH THE RAT

D.M. McKAYI D.W. HALTON' C.F. JOHNSTON* C. SHAW* lSchoo1 of biology and Biichemistry'and *Department University of Belfast, Belfast BT7 1NN

and I. FAIRWEATHERl, of Medicine, The Queen's

The expulsion of the rat intestinal tapeworm, Hymenolepis diminuta from the murine host is an immunologically-mediated phenomenon. In the present study, the H. diminuta-C57 mouse system has been used to examine any changes in endocrine cell number and selected regulatory peptides that may correlate with Male 6 - 8-week-old mice were infected with a the rejection response. 5-cysticercoid dose of H. diminuta and autopsied 10 days post-primary and 5 days post-secondary (given 28 days post-primary) infection. Two regions of the intestine (i.e. 20-30% and 60-70% with respect to distance from the pylorus) were screened immunocytochemically for the presence of serotoninpositive enterochromaffin cells, while the remaining three gut portions were Mice sham-infected with individually extracted for peptide quantification. Results have revealed a statistically Hanks' saline served as controls. significant increase in endocrine cell number in the 60-70% region of the intestine of infected mice. Significant deviations from control levels were observed for substance P, glucagon (both elevated), neurotensin, peptide histidine isoleucine and vasoactive intestinal peptide (all three lowered) in Radioimmunoassay of gastrin, gastrin releasing peptide, infected mice. motilin, pancreatic polypeptide and somatostatin revealed no differences Results suggest that the intestinal response between test and control mice. to a tapeworm parasite may, at least, be partially controlled by regulatory peptides.

IMMUNOGOLD LABELLING OF FMRFAMIDE-LIKE IMMUNOREACTIVITY IN THE BLOOD FLUKE SANGIJINICOLAINERMIS, PLEHN (1905) D. MCMICHAEL-PHILLIPS,J.W. LEWIS, M.C. THORNDYKE. DEPARTMENT OF BIOLOGY, ROYAL HOLLOWAY AND BEDFORD NEW COLLEGE, EGHAM, SURREY TW20 OEH S. inermis (Digenea:Sanguinicolidae)is a parasitic blood fluke found mainly in carp, and can cause severe economic losses, especially in young carp, in U.K. and EUrODean caru farms. No previous work has been undertaken on the regulatory processes of the-nervous system within S. inermis, and in this study FMRFamidelike immunoreactivity (IR) at the ultrastructural level was investigated. Adult worms (25 days old) were removed from laboratory infected mirror carp and processed for TEM. Much IR can be lost during this processing, but fixation in 4% paraformaldehyde and 0.5% glutaraldeyde, followed by embedding the entire worm in L.R. white resin, was found to give adequate ultrastructural preservation with the best retention of antigenicity. Ultrathin resin sections were incubated with anti-sera to FMRFamide, and IR was visualised using a 15nm gold probe. Controls were carried out using pre-absorbed anti-serum and nonimmune serum. FMRFamide-like IR was strongly evident within the everted cirrus pouch of the adult, localised in large granules found within the seminal vesical and associated endoplasmic reticulum. Granules surrounding the vas deferens also showed IR. Some IR was also found within the cerebral ganglion. FMRFamide-like IR appears to be closely associated with the reproductive system of the parasite and may be an important regulator of the reproductive process.