Back to Library

Stability of metacyclic variable antigen types (M-VATs) during the early stages of infection with Trypanosoma Congo Republiclense

Published by:
Publication date
Number of Pages
Type of Publication:
Articles & Journals
Focus Region:
Focus Topic:
Health & Diseases
Type of Risk:
Biological & environmental
Hopkins, J.; Luckins, A.G.; Rae, P.F.; Ross, C.A.

Expression of nine metacyclic variable antigen types (M-VATs) of Trypanosoma Congo Republiclense in chancres from infected rabbits was determined using monoclonal antibodies raised against metacyclic forms of trypanosomes. Trypanosomes present in chancres 7-9 days post-infection expressed M-VATs present in metacyclic populations of the parasites. The majority of M-VATs expressed showed little proportional change from those observed on metacyclic trypanosomes during this period although expression of one M-VAT increased, and another decreased. Although trypanosomes in chancres continued to express M-VATs, other VATs, not present in the M-VAT repertoire were also expressed and neutralization tests showed that new VATs appeared by 7 days after infection. In infected sheep neutralizing antibodies against M-VATs were detected by day 14 in lymph from efferent lymphatics draining lymph nodes in the region of chancres. Neutralizing antibodies directed against metacyclic were also present in the serum by day 14 and were still detectable for up to 35 days post-infection. Hence, it is likely that in the vertebrate host the trypanosomes multiplying in the skin at the site of tsetse bite express all M-VATs characteristic of that particular serodeme, enabling the host to develop immunity to all antigen types present in the M-VAT repertoire.