Global Advanced Research Journal of Biotechnology (GARJB)
January 2013 Vol. 2(1), pp 008-012
Copyright © 2013 Global Advanced Research Journals
Full Length Research Paper
Antibody responses to a recombinant Onchocerca volvulus antigen (Ov1.9) by onchocerciasis patients before and two months after Ivermectin treatment
Osue HO1, Edeghere H2, Galadima M3, Odama LD4 and Engelbrecht F5
1Nigerian Institute for Trypanosomiasis Research (N. I. T. R.), P.M.B. 2077, Kaduna, Nigeria
2National Onchocerciasis Control Programme (NOCP), Race Course Road, Kaduna.
3Formerly of Microbiology Department, Faculty of Science, Ahmadu Bello University (A B. U.), Zaria, Kaduna State, Nigeria
4National Pharmaceutical Research and Development, Idun, Abuja, Nigeria
5Hygeuine Institue, Abt. Parasitologie Im Neunheimer Feld 32469120 Heiderbeg, Germany.
Corresponding author E-mail: Osueho@yahoo.com
Accepted 23 May, 2012
Indirect sandwich enzyme-linked immunosorbent assay (ELISA) was used to measure serum IgG antibody responses to Onchocerca volvulus designated (Ov1.9) recombinant antigen in onchocerciasis patients (n=114) prior to initial ivermectin treatment. Paired sera (n=32) obtained 2months after treatment were also analyzed for changes in antibody levels in a sub-population at pre- and post-treatment. The difference between mean optical density (OD) values of IgG antibody level in proven cases (n=95) and the assumed endemic-normal (EN, n=19) of 0.58±0.23 versus 0.37±0.21, respectively was statistically significant (P<0.05) by the t-test of unpaired data. The non-endemic (NEN, n=7) control had mean OD value of 0.12±0.02. There was no significant difference between the sexes or among age groups and the infection subgroups (with or without presence of nodule and/or skin microfilariae mf). At a cut-off point of mean plus 2 standard deviations of OD value for the NEN control, the sensitivity of 87% in proven cases of onchocerciasis (n=95) and 89% in those with skin mf positive (n=62) proved that Ov1.9 may be suitable not as a single screening test reagent, but when in cocktail with one or more antigens. The higher mean OD value in those with chronic skin disease than those without clinical signs of onchocerciasis (n=39); with papular onchodermatitis (n=20) and optic nerve disease (n=12) subgroups was statistically significant by t-test of unpaired data (P<0.05). The heightened IgG antibody response to Ov1.9 with chronic skin disease is clearly indicative of the possible role parasite-specific antibodies may play in the immunopathology of the disease. There was no significant increase in mean antibody level two month post-ivermectin treatment; hence the antigen will not be useful for drug screening.
Keywords: Serology, sensitivity, Screening, Diagnosis, Antigens and Antibodies.
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