Characterisation of a panel of recombinant antigens from Echinococcus granulosus and their role in the immunological follow up, after treatment, of cystic hydatid patients from Turkana, Kenya

Bodell, AJ

Abstract

Cystic echinococcosis is a serious zoonotic disease caused by the metacestode
of Echinoccoccus granulosus inflicting significant morbidity and mortality in
many parts of the world. Treatment of human hydatid cases involves
chemotherapy with the drug Albendazole which has beneficial effects in some
cases but not others. Disease progression can be monitored by ultrasound
using the WHO classification system, but this only indicates large scale
changes in cyst morphology. Antibody responses to cyst fluid antigens have
previously been used to provide further information on follow up after treatment
and the current project explores the usefulness of a panel of novel recombinant
antigens in mapping antibody responses to cyst morphological changes.
Positive clones pET19b-EgFABP1-C10, pET19b-EgHSP70-C10, pET19b-
EgTPx-2Cb, pET19b-EgEF1-p/6-C9 and pET19b-EgAgB-C7 were selected and
used to synthesise recombinant fatty acid binding protein 1 (EgFABPI), heat
shock protein 70 (EgHSP70), thioredoxin peroxidase (EgfTPx) elongation factor
1-beta/delta (EgEF1-(3/6) and antigen B (EgAgB) fusion proteins respectively
carrying N-terminal His-tagged sequences. A panel of defined sequential sera
of Turkana origin (Kenya), untreated (n =9) and treated (n =22) was probed in
ELISA with the recombinant parasite antigens. Results show that different
antigens react differently towards total IgG and lgG1 and lgG4 isotype subclass
antibodies. Some antigens are associated with fluctuation in antibody levels at
or during the time of transition from one cyst morphology to that of another type,
whilst other antigens show little or no difference in reactivity. In some cases,
fluctuating levels of antibody are correlated to pre and post treatment with
albendazole. Antibodies are rarely static and fluctuate up and down during and
after treatment, indicating a more varied release of extraneous antigenic
material supplementary to those antigens normally associated with hydatid cyst
fluid. In a number of cases particular antibody profiles could be linked to
important changes in cyst structure and could have potential as markers of cyst
development. Throughout the current research, fluctuation in antibody
responses in CE sequential sera towards recombinant AgB has shown consistency in line with other authors. A high level of total serum IgG and
specific IgG subclass antibodies in response to REgTPx antigen and REgFABP1
has shown some association with active type cysts (CE1, CE2 and CE3).
Furthermore, peaking levels in activity of serum IgG and specific lgG1
antibodies in response towards REgEF1-p/8 antigen seem strongly correlated to
CE3 cysts just prior to, during, or upon transition to inactive type cysts (CE4 and
CE5). These serum antibody responses are also seen with REgHSP70 antigen
when other active type cysts (CE1 and CE2) show signs of deterioration. The
results therefore conclude that serological responses to each antigen may differ
in individual patients and that particular antibody reactivity may be useful in
predicting disease progression or regression. Recombinant EgFABPI and
EgTPx antigens may be functional as indicators of early cyst fertility and viability
respectively; REgEF1-p/6 antigen might be valuable as a marker of disease
regression and REgHSP70 antigen could be practical as an indicator of parasite
instability.

Citation

Bodell, A. Characterisation of a panel of recombinant antigens from Echinococcus granulosus and their role in the immunological follow up, after treatment, of cystic hydatid patients from Turkana, Kenya. (Thesis). University of Salford

• Thesis Type: Thesis
• Deposit Date: Jul 27, 2021
• Additional Information: Funders : British Society for Parasitology
• Award Date: Jan 1, 2012