Transmission of the Common Cold to Volunteers Under Controlled Conditions. Iv. Specific Immunity to the Common Cold*

Although the common cold is the most prevalent illness of humans, information on the antigenicity of the infectious agents and the immune response of the host to the infection has been difficult to obtain.Epidemiologic investigations have led to divergent hypotheses.The frequent repetition of colds, on the one hand, has suggested little or no immunity to reinfection.On the other hand, the diminution or disappearance of colds among isolated populations, even in an arctic climate, is compatible with the belief that persons develop im- munity to specific common cold agents (1, 2).Analysis of the influence of age upon susceptibility also is inconclusive with regard to acquired im- munity to the common cold.The frequency of common colds tends to decline with age beyond childhood (3-5), but in a survey of colds within a group of families apparent evidence of brief im- munity was observed after infection only among children (3).Transmission of the common cold to volunteers by filtered nasal secretions or nasopharyngeal washings offers the most direct approach to the problem.Several groups of investigators have shown that the common cold can be successfully transmitted to volunteers, but almost always it has been impossible to infect all of them.The inci- dence of experimental colds has been about 35 to 50 per cent (6, 7).The basis for susceptibility or resistance is not known but might be specific im- munity.In previous studies we have shown that the infectivity of filtered infectious nasal secretions can be neutralized by the globulin fraction, but not by albumin, from pooled human plasma (8).