Antibody production in milk serum after virus instillation of goat mammary gland. IV. Experiments with protective properties of specific influenza antibody associated with lactogammaglobulin.

The protective property of specific antibody against influenza PR8 associated with lactogammaglobulin was investigated. The antibody was given to groups of mice by the intramuscular and respiratory routes before exposure to adapted virus contained in aerosols of two concentrations, one being capable of killing all unprotected mice. A temporary, but well-marked, passive immunity was demonstrated in those receiving antibody intramuscularly; if a second injection was given later, resistance was prolonged. A second respiratory challenge of concentrated adapted virus given to survivors three weeks later revealed evidence of immunity. Antibody given by the respiratory route gave varying results. When given once, either a fleeting protection or protection which led to an active immunity followed. This appeared to depend on whether a degree of propagation within the lung took place for several days after challenge. When antibody was given daily and propagation failed to take place, only a temporary immunity resulted and the mice were unprotected against another challenge.