The effects of hypobaric hypoxia on specific B cell responses following immunization in mice and humans

In order to get some insight on the physiology of the immune system during prolonged exposure to hypobaric hypoxia we evaluated the effects of high altitude on the in vivo immune response to a T-independent antigen. A group of 18 men who participated in a scientific project EV-K2-CNR to Mount Poumori, Nepal for 20 d at 4,930 m (16,174 ft) were immunized with a single subcutaneous dose of antimeningococcal vaccine Menpovax A + C (Sclavo) containing 50 micrograms of polysaccharide A (PsA) and 50 micrograms of polysaccharide C (PsC) of N. meningitidis. A group of 18 men of comparable age were vaccinated at sea level. Antibody titers against both polysaccharides were determined by enzyme-linked immunosorbent assay (ELISA) before and 18 d after vaccination. All subjects examined developed a good antibody response and no statistically significant differences were observed between the two groups. Spectrotypic analysis of antibody response to PsC was also performed by isoelectric focusing. No qualitative differences in the antibody response to PsC were found in the hypoxia-exposed group with respect to the control group. A group of 10 BALB/c inbred mice were kept in a hypobaric chamber at 5,500 m (18,000 ft) for 30 d. After 10 d, the mice were vaccinated with 1 micrograms of Menpovax A + C. Anti-PsA and anti-PsC antibodies were quantified by ELISA in sera collected at day 0 and 30. A control group of 10 mice of the same strain underwent the same study protocol but at sea level. Both groups developed a good antibody response to both polysaccharides and no significant differences were observed.(ABSTRACT TRUNCATED AT 250 WORDS)