THE USE OF ADJUVANTS IN STUDIES ON INFLUENZA IMMUNIZATION : I. MEASUREMENTS IN MONKEYS OF THE DIMENSIONS OF ANTIGENICITY OF VIRUS-MINERAL OIL EMULSIONS

Untoward reactions at the site of inoculation were not observed in monkeys vaccinated with influenza virus incorporated in a water-in-oil emulsion without acid-fast bacilli. Studies were then made to measure some of the dimensions of antigenicity of these emulsions to evaluate the extent of the immunologic adjuvant effect. This included measurements of height and persistence of the antibody response to inoculation and measurements of the extent to which the vaccine could be diluted and still induce antibody formation; i.e., antigenic extinction. In addition, comparisons were made of the rates of development of hemagglutination-inhibiting, virus-neutralizing, and complement-fixing antibody activities to determine the relationship among these three properties of the serum of immunized animals. It was found that levels of antibody many fold higher were induced by the virus-adjuvant mixtures as compared with virus in an aqueous menstruum, and that the level of antibody induced was related to the quantity of antigen incorporated in the emulsion. The stock vaccine when emulsified could be diluted 100,000-fold and was still active in antibody formation whereas a 100-fold dilution of the antigen without emulsification was essentially ineffective. Equivalent quantities of virus in 0.1 ml. or 1.0 ml. of emulsion induced antibody responses that were indistinguishable with respect to level or persistence. In comparing the course of antibody development it was found that hemagglutination-inhibiting, virus-neutralizing, and complement-fixing antibodies develop at different rates; careful analysis of the data derived from the present study together with other observations warrant the conclusion that these antibody activities are not present in constant proportion and are independent of one another. The implications of this observation and of the others mentioned above are discussed

THE ANTIGENIC POTENCY OF EPIDEMIC INFLUENZA VIRUS FOLLOWING INACTIVATION BY ULTRAVIOLET RADIATION

A study of the antigenic potency of influenza virus inactivated by ultraviolet radiation has been made. Virus so inactivated is still capable of functioning as an immunizing agent when given to mice by the intraperitoneal route. In high concentrations inactivated virus appears to be nearly as effective as active virus but when quantitative comparisons of the immunity induced by different dilutions are made, it is seen that a hundredfold loss in immunizing capacity occurs during inactivation. Virus in suspensions prepared from the lungs of infected mice is inactivated more rapidly than virus in tissue culture medium. A standard for the comparison of vaccines of epidemic influenza virus is proposed

THE USE OF ADJUVANTS IN STUDIES ON INFLUENZA IMMUNIZATION I. MEASUREMENTS IN MONKEYS OF THE DIME.NSlONS OF ANTIGENICITY OF VIRus-MINERAL OIL EMULSIONS*

Rather early in studies on influenza immunization in animals as well as in man, it was realized that immunizing effect, as reflected in antibody response induced by the vaccines employed, was limited and of relatively short duration. For these reasons (1) a variety of methods were explored for enhancing and prolonging the protective effect induced by vaccination (2-7). None, however, provided such striking results as those obtained in studies in animals reported by Friedewald (6), and in studies in man reported by Henle and Henle (7). These investigators used vaccines consisting of virus in water-in-oil emulsions in the manner developed in recent years by Freund (8). Although the immunologic data derived by Friedewald and the Henles were outstanding, in comparison to the effects induced by vaccines consisting of virus in an aqueous medium alone, the immunologic success was blighted by the occurrence of undesirable reactions at the site of inoculation. The problem remaining after these experiences seemed merely to be one of reducing or eliminating the untoward local reaction while retaining the immunologic advantage