Antibody patterns specific to mannoprotein in candidiasis and normal host

Abstract

To study the antibody profiles to mannoprotein in candidiasis, fifteen sera of HIV – infected patients with oral candidiasis and five sera with systemic candidiasis who visited King Chulalongkorn Memorial Hospital were recruited. Thirty normal healthy host sera obtained from medical students and staffs of faculty of Medicine, Chulalongkorn University were used as control group. All HIV–infected patients had CD4⁺T cells number ≤ 200 cell/mm³. Screening for the presence of Candida specific IgG antibody was done by using Enzyme–linked immunosorbent assay (ELISA). While titers of Candida specific IgG in 93% of the patients with oral candidiasis and 83% of the control group are ≤ 1:100, the titers of all patients with systemic candidiasis are ≥ 1:200. Determination of mannoprotein by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS – PAGE) revealed that it is composed of at least 12 antigenic components, 52, 50.5, 46.5, 45.5, 43.5, 42, 38, 36.5, 32.5, 29, 25, 22.5 kilodaltons. All sera were analysed the specificity against mannoprotein by Western blot assay. The numbers of reactive band from each sera were classified and set as pattern. In healthy group, there were 15 patterns while oral candidiasis group and systemic group were found 12 and 5 patterns, respectively. The most common antigenic components found in almost all sera of any group were 46.5, 43.5 and 36.5 kilodaltons. Interestingly, antigenic component molecular weight of 52 kilodaltons was detected in 60% of systemic candidiasis compared to only 6.7% in oral candidiasis group and none (0%) in healthy host. And antigenic component molecular weight of 29 kilodaltons was detected in 20% of oral candidiasis and none (0%) in systemic candidiasis and healthy host. Another component of 505 kilodaltons was also found in 60% of systemic candidiasis and few in oral candidiasis group (13.3%) and healthy host (9.1%). In conclusion, this study revealed 2 components, 52 and 50.5 kilodaltons might be remarkable antigenic markers for differential diagnosis of systemic candidiasis whereas 29 kilodaltons might be important antigenic markers for differential diagnosis of oral candidiasis.