STUDIES ON EXPERIMENTAL INFLUENZA IN MICE. VII

SITES OF ANTIBODY PRODUCTION, WITH PARTICULAR EMPHASIS ON THE DETECTION OF HIGH ANTIBODY TITER IN LUNG LESIONS

Abstract

Antibody level in the serum of mice infected with influenza virus via three different routes has been already described. In discussing the participation of immune mechanism on the growth of virus as well as on the fate of experimental animals, rather the series of events accompanied to the establishing process of immune status was thought to be a matter of interest. Having this kind of consideration in mind, antibody titers in various organs of infected mice have been pursued by means of hemagglutination inhibition test.
Prior to the experiment, the procedure to remove all of the non-specific hemagglutinin inhibitors from various organ extracts was examined. This was easily done by treating the specimen with cholera filtrate, even when the heated Lee virus was used as an indicator. Then the antibody titer against the PR8 virus, the strain which had been known to be most insensitive to various α-inhibitors has been examined.
Main results obtained along the study will be summarized as follows:
1) The amount of α-inhibitor both in lung and bronchial washings after intranasal or intraperitoneal infection has been pursued. Inhibitor titer curve obtained against the day was just a mirrorimage to that of virus growth.
2) After the inhalation of sublethal amount of PR8 virus or after the intraperitoneal injection of large dosis of alive or formaline-inactivated PR8 virus, the antibody titers of serum, bronchial washing, lung, liver and spleen were examined at appropriate intervals. To visualize the production curve of antibody in any organs concerned, a value “antibody index” was calculated. When antibody titer in some organs at some stage was taken as a numerator, and antibody titer in the sera at the same stage was taken as a denominator, this value was obtained.
Only in spleen, the value of antibody index was higher than 1 at an early stage of infection or immunization. This kind of early antibody rise in spleen was never observed at the time of passive immunization when rabbit serum prepared against PR8 virsu was injected intravenously.
3) Consolidation parts of the lung found at late stage of infection was also believed to be responsible for the antibody production. The value of antibody index obtained with consolidation parts was apparently higher than that of healthy parts of the same lung, and was almost 2.
4) However the antibody found in bronchial washing was thought to be of different nature when compared to that in lung. With the former, the increase in titer was demonstrated by nonspecific stimuli, whereas the fact did not hold true with the latter.