| dc.description.abstract | In any attempt to improve sensitivity and efficacy of
serodiagnostic tests in visceral leishmaniasis, it has
become increasingly important to study the antigenic
reportoire of Leishmania donovani, the causative organism.
Three strains of L. donovani promastigotes were cultured
in RPMI 1640, supplemented with foetal calf serum and
antibiotics, at 26°C. Late log phase/early stationary phase
promastigotes were harvested and the parasites disrupted by
freeze thawing. Crude and soluble antigens were made,
which were stored, in aliquots, at -70°C.
The antigens were analysed by SDS - PAGE separation and
immunoblots were carried out on sera from thirty kala-azar
patients admitted to the Clinical Research Centre (Kenya
Medical Research Institute, Nairobi), before treatment up to
12 months after treatment, so as to identify the particular
antigens involved in immunity and~·could be
'* of use in
immunodiagnosis. ..:
There was no difference in the antigenic patterns and
antigenicity between the three strains of L. donovani
studied. Individuals cured of kala-azar did not develop
antibodies that differed in specificity to those undergoing
treatment .
... .'," .
Patterns of antigen reactivity were compared by using sera
from individuals with malaria, tuberculosis, schistomiasis
and hydatidosis infections. Sera from individuals with
these infections did not recognise L. donovani antigens.
(viii)
Trypanosomiasis sera recognised the 22-30 kD, 40 kD, 49 kD,
56 kD, 60 kD, 63 kD, 65 kD, 66 kD, 82 kD and 110 kD.
~ donovani antigens of 66-74 kD region were recognised by
all individuals with kala-azar. This region was found to
contain at least three distinct bands. These bands were
eluted from SDS-PAGE gels and used to diagnose L. donovani
infection by ELISA (Enzyme-linked immunosorbent assay).
Whereas the crude gave false positive results with other
infection sera, the eluted 66-74 kD protein was 100%
specific and sensitive in the diagnosis of visceral
leishmaniasis. | en |
