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INFLUENCE OF SOLAR RADIATION ON IMMUNITY, II [Vol. XXI, Part III,
Immunity tests on buffaloes and goats revealed that they were all immune at the
end of three months after vaccination. This was, perhaps, due to the higher per-
centage of potency of immune sera of both the groups, sun and shade, as found out
by the potency tests. It appears, there exists a direct relation between the results
of the potency tests and immunity tests.
The results of the experiments, together with the interpretations, given above
indicate that the solar radiation has detrimental influence on the formation of anti-
bodies in the immunized animals exposed to the sun for a few days after vaccina
tion. Systematic investigation into this important problem has not been taken up
so far by any worker. The line now opened up by the author offers great oppor-
tunities for other workers to pursue it further.
SUMMARY
Hill-bulls, buffaloes and goats were immunized against rinderpest with a single
dose of goat tissue vaccine and from the next day of vaccination, the 'Sun group'
was daily exposed to the sun for a period of about 8 to 10 days and the duration of
exposure on each day was regulated by observing the rise of body temperature and
respiration count of the exposed animals. They were transferred back to the shed
before distressing symptoms appeared. The ' Shade group ' was kept inside the
shed and was not exposed to the sun during the corresponding period. The influence
of Solar radiation on the formation of specific antibodies, as judged by the potency
test of the immune sera, was studied. Both the groups were bled for immune sera
on the 21st day after vaccination. Two composite mixtures of sera one for each
group were obtained. The results of the potency tests in three out of four experi-
ments revealed that the percentage of potency of the ' Shade group serum ' was
more when compared with that of the ' Sun group serum'. In the fourth experi-
ment, the percentage of potency of immune sera of both the groups was found to be
equal.
The influence of solar radiation was also studied on (a) the incubation period,
(6) the clinical symptoms, (c) the mortality and (d) the immunity conferred. With
regard to the incubation period it was observed that in two out of four experiments
the incubation period of the 'Sun group' was shorter than that of the ' Shade
group ': but in case of other two experiments, the incubation period was the same
for both the groups. In all the four experiments on rinderpest, the severity of the
reactions in the 'Sun group' was much more pronounced than that in the ' Shade
group'. Total number of deaths directly due to rinderpest or its after-effects among
the reactors of the 'Sun group' was more than the total number of deaths among
the reactors of the ' Shade group '. Immunity tests conducted three months after
vaccination revealed that in the first experiment with hill-bulls, there was a partial
breakdown of immunity in the 50 per cent of the animals of the 'Sun group'. All
the other animals of the same experiment were found to be immune. In the second
experiment with hill-bulls, there was a complete breakdown of the immunity
resulting in death in 3 animals of the ' Shade group ' and 4 animals of the 'Sun
group', and there was a partial breakdown of immunity in 3 animals on each side
(recovered after mild attack of rinderpest). Only 2 animals of the ' Shade group '
were found to be still immune (The percentage of potency of immune sera of the
'Sun group' of the first experiment and of both the groups of the second expreiment