The implications of the F6 reactive profile need further study. Elevated IgG4 levels were reported in mf carriers (ASM) and tropical pulmonary eosinophilia (TPE) cases26C30. n=10) were assayed for F6-specific IgG1, IgG2, IgG3 and IgG4 by ELISA using SDS-PAGE-isolated F6 fraction of adult worms. Results: Significantly high levels of F6-specific IgG1, IgG2 and IgG3 were found in CL (and and transmitted by mosquitoes is recognized as one of the world’s most incapacitating diseases in tropical areas. Worldwide around 120 million people are affected by the infection of whom 40 million show the chronic disease manifestations: elephantiasis and hydrocele1 and a further one billion (18% of the world’s population) are at risk of infection2. The adult worms inhabit the lymphatics, where they survive for prolonged periods, and produce millions of first-stage larvae (microfilariae; mf), which circulate in the peripheral blood. Following ingestion of blood by mosquitoes, mf develop to the third larval stage (L3) in the mosquito. The cycle of infection is re-initiated by the mosquito during next blood meal. A major enigma is the identity of parasite products that modulate host’s immune response leading to the two extremes: largely peaceful survival of the parasite in the host without causing disease (asymptomatic microfilaremics), or development of the chronic disease manifestations such as elephantoid deformities and hydrocele through repeated episodes of adenolymphangitis and lymphoedema. Inflammatory cytokines and immunological hyperactivity of the host may, on one hand, promote establishment of the infection3 and JNJ-7706621 on the other, lead to disease manifestations4. Such diverse responses are thought to be due to the ability of live and Rabbit Polyclonal to M-CK dead parasite products to stimulate release of either predominantly pro- or anti-inflammatory cytokines under different conditions. Our earlier studies revealed that live stages of the parasites are capable of stimulating release of both pro- and anti-inflammatory cytokines5. Maizels and Lawrence6 also showed that an acute exposure to mf induced an inflammatory type 1 response whereas L3 and adults induced primarily type 2 responses in a mouse model. We JNJ-7706621 recently isolated BmAFII, a Sephadex G-200 eluted fraction of adult worm extract, and found it to be predominantly proinflammatory, and it protected the rodent host from infections8. Further studies revealed that the strong proinflammatory proteins are localized to a 54-68kDa fraction F6 and immunization with F6 protected jird and from infection via Th1/Th2 type responses including IgG2a antibody response9. MALDI-TOF analysis of the fraction revealed five proteins, of which three were immunostimulatory (were collected from peritoneal cavity of infected jirds11 having 120-150 days old infection. Soluble somatic extract of the worms was prepared and resolved by 10 per cent sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) as described by Laemmli12. Resolved fraction F6 (54-68kDa) identified with the help of pre-stained molecular weight markers run simultaneously was cut out using JNJ-7706621 sharp and clean scalpel9. Proteins from gel strips were electro-eluted (Electroeluter, Millipore, India), concentrated (Centricon?; 10kDa cut-off; Millipore, India), and estimated13. The molecular weight of the purified proteins was confirmed in SDS-PAGE (Fig.) and stored in aliquots at -20C till use. Open in a separate window Fig. SDS-PAGE showing F6 of adult worm somatic extract (BmAS) was run on SDS-PAGE and the F6 band was cut out, eluted with gel eluter (Electroeluter, Millipore, India) and run again on JNJ-7706621 SDS-PAGE to confirm the molecular location. to F6 alone induced epithelioid granulomas in the draining lymph nodes (unpublished observation) indicating a possible role of F6 in filarial pathology. High IgG2 levels in ASM subjects appear to be related to pathology as ASM subjects are now known to show hidden early lymphatic pathology19. However, Noordin antigens are known to elicit different IgG subclass profile in different clinical categories of subjects23,24. L3 antigen BmNIP3 showed elevated levels of IgG1 and IgG2 antibodies in EN subjects and largely IgG3 in chronically infected patients and strong reactivity with IgG1 in microfilaraemic individuals25. The IgG3 reactivity of F6 in EN subjects thus appears to be common between L3 and adult derived (F6) antigens. However, it is clear that the profile of all IgG subclasses reactive to adult derived F6 need not be identical to that shown by L3 antigens. The implications of the F6 reactive profile need further study. Elevated IgG4 levels were reported in mf carriers (ASM) and tropical pulmonary eosinophilia (TPE) cases26C30. In the present study, F6-specific IgG4 levels in ASM cases were not significantly high as compared to NEN-U. This difference may be due to the fact that F6 which does not elicit IgG4 response is only one fraction of the complex parasite antigens available in the mf carriers and TPE cases and the antigens other than F6 might be responsible for the IgG4.