Murine monoclonal anti-H as typing reagent.

BACKGROUND & OBJECTIVE: The antigen H present on the surface of red cells in varying concentration, is maximum in O group red cells, but absent in Bombay phenotype individuals. This differentiation is generally detected by seed extracts of Ulex europaeus. The titre of such an extract is usually low and is subjected to batch variation. Hence, we carried out this study to raise potent murine monoclonal antibody against H antigen. METHODS: Spleen cells of female BALB/c mice immunized with O group red cells were fused in presence of polyethylene glycol (PEG) 1500 with a mouse myeloma cell line Sp2/0 Ag14 in hypoxanthine aminopterine thymidine (HAT) selective medium and incubated at 37 degrees, 5 per cent CO(2) and 95 per cent humidity for a week. RESULTS: The culture supernatants showing anti-H activity, were further subcloned and two clones 3E8A10 and 3E8A11 generated which showed a good potency, avidity and specificity. INTERPRETATION & CONCLUSION: The anti-H clones thus produced indigenously provided a potent reagent in distinguishing normal O group from Bombay phenotype individuals. The unlimited availability makes this reagent cost-effective to ensure a constant supply of hybrid clones with the similar specificities.

Production of murine monoclonal anti-B.

BACKGROUND & OBJECTIVE: Monoclonal antibodies against red blood cell antigens used in research and as diagnostics in India are commercially procured from western countries. Indigenously generated potent clones are not available in India. Hence, the objective of the present study was to raise potent murine monoclonal antibodies against A, B and H blood group antigens indigenously and establish a stable clone of anti-B secreting cells. METHODS: Spleen cells of female BALB/c mice immunized with B group red blood cells were fused in presence of polyethylene glycol (PEG) 1500 with a mouse myeloma cell line Sp 2/0 Ag. 14 in hypoxanthine aminopterine thymidine (HAT) selective medium and incubated at 37 degrees C, 5 per cent CO(2) and 95 per cent humidity for a week. RESULTS: The culture supernatant of the wells showing anti-B activity, were further subcloned and a clone 2C4D5F10 was generated which showed a good potency, avidity and specificity. INTERPRETATION & CONCLUSION: The anti-B clones thus produced indigenously provided a useful reagent in blood group typing. The unlimited availability unlike polyclonal antisera makes this reagent more cost-effective. It also ensures a regular supply with the similar specificity.

A study of anti-neutrophil cytoplasm antibodies in systemic vasculitis and other related disorders.

BACKGROUND: Anti-neutrophil cytoplasm antibodies (ANCA) play an important role as specific and sensitive markers for small vessel vasculitis and in some other systemic disorders. Indirect immunofluorescence test, known as the "Gold Standard" for screening of ANCA, can be further substantiated by ELISA for confirmation and for identifying sub-specificities like anti-Myeloperoxidase (anti-MPO), anti-Proteinase 3 (anti-PR3) and anti-Lactoferrin (anti-LF). AIMS: The present study was undertaken to investigate the incidence, specificities and strength of ANCA in suspected vasculitis cases and to correlate their presence with that of these auto-antibodies and with the disease. SUBJECTS AND METHODS: Sera from 130 clinically suspected vasculitis patients were studied. Indirect immunofluorescence microscopy (IIF) was used to identify cytoplasmic (c-ANCA), perinuclear (p-ANCA) and atypical (X-ANCA) patterns using ethanol and formalin fixed polymorphonuclear cells (PMN) and HL-60 cells from a human promyelocytic leukaemic cell line as substrates. ELISA was performed for identifying ANCA sub-specificities to anti-MPO and anti-PR3 and HEp-2 cells were used for detection of anti-nuclear antibodies (ANA). RESULTS: ANCA positivity was noted in 42.3% of these patients, wherein p-ANCA positivity rate was 34.6% and c-ANCA positivity was noted in 5.4% subjects. Three patients showed the unusual X-ANCA positivity. ELISA determined the sub-specificities: Out of 45 p-ANCA positive patients, 38 patients (84.4%) had anti-MPO and out of 7 c-ANCA positive patients, 5 patients (71.4%) had anti-PR3 antibodies. One patient with Class IV Lupus Nephritis, showed both anti-MPO and anti-PR3 antibodies and 17.8% p-ANCA positive patients had anti-Lactoferrin antibodies. CONCLUSIONS: Use of the Immunofluorescence method coupled with identification of ANCA sub-specificities by ELISA, is recommended for detection of ANCA in clinically suspected cases of small vessel and other systemic vasculitis.

Autoantibodies, immunoglobulins, complement and circulating immune complexes in acute malaria.

BACKGROUND: Malaria caused by Plasmodium vivax and Plasmodium falciparum is common in the Indian subcontinent. Studies conducted elsewhere have suggested that malarial infection causes intense immunostimulation. We screened patients with malarial infection for autoantibodies and measured the immunoglobulin, circulating immune complex and complement levels to determine the extent of immunological alterations in these patients. METHODS: One hundred adults with acute malarial infection confirmed by examination of the peripheral blood smear and 25 age- and sex-matched controls were studied. An autoantibody screen and serum immunoglobulin complement (C3 and C4) and circulating immune complex levels were measured at the time of admission and 4 weeks after they became afebrile. A direct Coomb's test was also done. RESULTS: Anti-ssDNA, anti-dsDNA and rheumatoid factor were positive at the time of admission in 51, 30 and 38 patients respectively. None of the controls were positive for these autoantibodies except for one who was positive for rheumatoid factor. The IgM, IgG and IgA levels were raised in 16, 25 and 36 patients respectively. Circulating immune complex levels were raised in 32 patients and complement C3 and C4 were low in 8 and 31 patients. Follow up studies at 4 weeks in 19 patients showed that the autoantibodies were negative. However, the immunoglobulin, C4 and circulating immune complex levels remained elevated. Six per cent of patients had a positive direct Coomb's test with reticulocytosis at the time of presentation. CONCLUSION: Acute malarial infection can cause false-positive results for anti-ssDNA, anti-dsDNA and rheumatoid factor and may also cause a rise in the serum immunoglobulin, complement and circulating immune complex levels.