Elva Minuse

Influence of Saliva upon Hemagglutination by Influenza Virus.

Summary Saliva of human adults possesses the capacity to inhibit agglutination of erythrocytes by influenza virus. Under the conditions of study the effectiveness varies among individuals and at different times. Its action is not significantly affected by heating at 56° C for 30 minutes; nor is its behavior influenced by heating of the virus. Nevertheless, the action of the inhibitor appears to be upon the virus rather than upon the erythrocytes. The nature of the inhibitor has not been determined but it is suggested that saliva represents a physiologic source of materials such as have been shown to interfere with hemagglutination in in vitro systems.

An imporved procedure for measuring neuraminidase antibodies by hemagglutination-inhibition.

Neuraminidase antibodies are known to inhibit hemagglutination by X-15 and X-15 (HK) recombinant viruses. However, the level of inhibition observed varies when different batches of chicken erythrocytes are employed, and the test generally detects neuraminidase antibodies with less sensitivity than an enzyme inhibition test. By titrating neuraminidase antibodies in the presence of anti-IgG globulins, with appropriate specificity, the hemagglutination-inhibition activity of neuraminidase antibodies is enhanced and the effect of cell variation is minimized. Consequently results obtained with this modified method for titrating neuraminidase antibodies become comparable to those obtained by measuring enzyme-inhibition. The improved hemagglutination-inhibition procedure possesses the important advantages of greater convenience and economy. Similar enhancing effects may also be obtained with egg white and guinea pig serum.

Resemblance of a Strain of Swine Influenza Virus to Human A-prime Strains.

Conclusions 1. A strain of swine influenza virus (Oti), isolated in 1939, has been re-investigated by serological means and found antigenically to resemble some members of the human A-prime influenza virus group. 2. Significant increases in the levels of anti-body against this swine strain of influenza virus were detected in the convalescent blood specimens of children who had had experience during the A-prime influenza epidemic of early 1947. High titers of antibody were also found against the current A-prime strains. 3. Adults involved in the same epidemic also showed significant antibody increases against the same swine strain and the current A-prime and Type A strains. 4. Results of cross hemagtglutination inhibition tests with specific ferret anti-sera supported the observations made from the serological tests with human sera. 5. The relationship of this swine strain to members of the A-prime group has been discussed.