A note on the immunogenicity of ultra-violet irradiated vaccinia virus in man

Abstract

A preparation of vaccinia virus inactivated by ultra-violet irradiation under strictly controlled conditions, and shown to produce neutralizing antibody and resistance to challenge in rabbits, was active in only about half of 37 human volunteers. It was not, therefore, likely to be usefully immunogenic in man. In the largest single test, 15 of 25 men had unmodified primary skin reactions when challenged with living virus, although five of these had circulating antibody. On the other hand, only three of 10 men who responded to challenge with modified or negative reactions, had no circulating antibody.In man the presence of circulating antibody does not necessarily indicate resistance to infection in the skin, nor does skin immunity always indicate the presence of circulating antibody.

The immunogenicity of heat-inactivated vaccinia virus in rabbits

“…Collier, McClean & Vallet (1955) obtained encouraging results in rabbits using ultra-violet-irradiated virus, both in terms of antibody produced and immunity to challenge, but results in a pilot study in man (Kaplan, McClean & Vallet, 1962;Kaplan, 1962;Kaplan et al 1965) were regarded as unsatisfactory, in that the immunity to challenge was not reproduced though antibody was elicited. Amies (1961), RamanaRao (1962) and McNeill (1965) showed formalintreated virus to be immunogenic in rabbits and Herrlich (1959;1964) has used such a vaccine for pre-immunization before vaccination with live virus without, however, completely banishing complications.…”

For debate: Is disinfection of specimens, which may contain unknown or bio-terrorist organisms, essential before electron microscopic examination?

“…In addition, the efficacy of disinfection may decline sharply as the protein content rises, as has also been described for ultraviolet irradiation. 7 Another factor to consider is that precipitants may clump the particles together reducing random distribution within the specimen, and making identification more problematic.…”

Wanted, dead or alive: New viral vaccines

“…In one study using UV-inactivated virus injected subcutaneously (Kaplan et al, 1962), neutralizing antibody titers were observed in only about half of vaccinees (19/37 subjects = 51%), and the low neutralizing activity was often near the limit of detection. Secondary challenge with live vaccinia virus by scarification indicated that only 8/25 (32%) of the subjects vaccinated with UV-inactivated virus showed a modified skin reaction indicative of antiviral immunity.…”