Analysis of salivary gland proteins of the mosquito Armigeres subalbatus.

Quantitative studies of total salivary gland protein of Armigeres subalbatus mosquito revealed that the total salivary gland protein increased dramatically during the five days after emergence as adults. The amount of salivary gland protein of female and male mosquitos at day five after adult emergence were on the average 11.55 and 1.32 microg/pair gland respectively. SDS-PAGE studies showed that salivary gland protein profiles of Armigeres subalbatus demonstrated 9 major polypeptide bands of 68, 65, 60, 55, 40, 30, 28, 21, and 15 kDa. The 21 and 65 kDa bands were found only in the distal lateral region of the mosquito salivary gland and were depleted after the female mosquito took a blood meal.

Differential recognition of Brugia malayi antigens by bancroftian filariasis sera.

Individuals residing in an area endemic to Wuchereria bancrofti infection were broadly categorised as endemic normals (EN), microfilaraemics (mf + ve) and elephantoids i.e., chronic lymphatic filariasis (EL). The immune status of these three groups was examined in terms of (i) specific antibody levels; (ii) ability to induce antibody dependent cellular cytotoxicity (ADCC) to microfilariae; and (iii) ability to recognise different microfilarial antigens by immunoblotting. All three groups of endemic residents were indistinguishable in their antibody levels as measured by ELISA with B. malayi microfilarial antigen. Many endemic normal sera and most elephantoid sera exerted strong cytotoxicity against W. bancrofti microfilariae whereas none of the mf + ve sera had any such activity. Immunoblotting studies revealed that a protein with mol. wt of 79 KDa was the only one among the proteins of B. malayi microfilarial extracts that was consistently recognised by sera from all endemic residents. Endemic normal sera and elephantoid sera, which exerted maximum cytotoxicity, together specifically recognised three proteins with molecular weights 25, 58 and 68 KDa and these three proteins could be among the candidate antigens that induce resistance to filarial infection.

Antigenic analysis of excretory-secretory products of Wuchereria bancrofti and Brugia malayi infective larval forms by SDS-PAGE.

Excretory-secretory (ES) products of W. bancrofti and the closely related B. malayi infective larval forms were analysed for their antigenic activity by SDS-PAGE followed by Western blotting as well as by gel elution-sandwich ELISA using filarial serum immunoglobulin-G (FSIgG) as a capture antibody. In W. bancrofti infective larval ES products, the protein molecules of 66, 46, 35, 33, 30 and 14 kDa molecular wt. showed antigenic activity by immuno blotting technique. In sandwich ELISA technique eventhough all SDS-PAGE fractions except ESA 6 (55-47 kDa) showed antigenic positivity, the fractions ESA 8 (37-31 kDa) and ESA 9 (31-25 kDa) showed high reciprocal antigen titre of 262144 and 32768 respectively. In B. malayi infective larval ES products, the protein molecules of 109, 102, 97 and 77 kDa molecular wt. showed reactivity with FSIgG by blotting technique, where as in sandwich ELISA except ESA 7 (47-37kDa), all fractions showed antigenic positivity. However, these fractions failed to show high antigen titre similar to W. bancrofti ES products with FSIgG.

Fractionation and characterization of urinary filarial antigen in bancroftian filariasis.

Urine samples from microfilaraemic patients were concentrated and fractionated by gel chromatography on Ultrogel AcA 44. Four protein fractions labelled as UFA C1, UFA C2, UFA C3 and UFA C4 were tested for filarial antigenicity by sandwich ELISA. UFA C1 and UFA C2 showed antigenic activity. On further analysis by SDS-PAGE, UFA C1 and UFA C2 showed antigenic components with MW ranging from 10.4 K to 123 K. UFA C1-1 and UFA C2-2 showed high antigen titre in ELISA. Urinary albumin was observed as a major component in UFA C2. Absorption of albumin from UFA C2 enhanced its antigenic activity considerably. As little as 0.01 pg antigenic protein per test was found to be sufficient for the detection of filarial antibody in ELISA. Biochemical characterization indicated a glycoprotein nature of UFA C2.

Detection of filarial antibodies in Malayan and Bancroftian filariasis by the indirect fluorescent antibody test, using different filarial antigens.

Indirect fluorescent antibody tests (IFAT) using Wuchereria bancrofti infective larvae as antigen had the highest positivity rates in detecting Malayan and Bancroftian filariasis as compared to IFAT using antigens prepared from 5 other animal filarial species, Brugia pahangi, Dirofilaria immitis, Dipetalonema viteae, Litomosoides carinii and Onchocerca gutturosa. This study also recommends the use of human filarioids as the source of antigen in serological tests. However, before B. malayi and especially W. bancrofti can be easily available from the common laboratory animals. B. pahangi seems to be a suitable source of antigen for use in serological tests for human lymphatic filariasis.