title: Cellular immunity in measles vaccine failure: demonstration of measles antigen-specific lymphoproliferative responses despite limited serum antibody production after revaccination.
abstract: Measles antigen-specific immune responses were evaluated 1 and 6 months after revaccination in 60 previously vaccinated subjects (9.4 +/- 3.4 years of age) who had either undetectable or low plaque reduction neutralization (PRN) titers (< 200). PRN titers were increased in all subjects at 1 month (590 +/- 61; range, 129-2513) but fell again in 66% of subjects by 6 months (214 +/- 29; range, 30-794). At 6 months, 23 (38%) had subprotective (< 120) or borderline (< 200) PRN titers. Lymphoproliferative responses to measles virus antigens were low overall before revaccination (mean stimulation index [SI], 2.6 +/- 0.4; range, 0.5-13.5) but were readily detectable at 1 (SI, 145.8 +/- 2.6; range, 1.4-80) and 6 months after revaccination (SI, 9.4 +/- 1.8; range, 1.1-87). Before revaccination, 10 of the subjects (50%) with low positive PRN titers had SIs > or = 3. At 6 months after revaccination, 18 subjects (78%) with PRN titers < or = 200 had SIs > or = 3. These data suggest that cellular responses to measles virus may be better sustained than antibody titers after vaccination and revaccination in some subjects.
authors.affiliation: McGill Centre for the Study of Host Resistance, Montreal General Hospital, Quebec, Canada.
authors.forename: B J
authors.initials: BJ
authors.lastname: Ward
authors.forename: N
authors.initials: N
authors.lastname: Boulianne
authors.forename: S
authors.initials: S
authors.lastname: Ratnam
authors.forename: M C
authors.initials: MC
authors.lastname: Guiot
authors.forename: M
authors.initials: M
authors.lastname: Couillard
authors.forename: G
authors.initials: G
authors.lastname: De Serres
mesh_terms: D000914:Antibodies, Viral / Q000096:biosynthesis*; D000956:Antigens, Viral / Q000276:immunology*; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007117:Immunization, Secondary; D007223:Infant; D007958:Leukocyte Count; D008213:Lymphocyte Activation; D008297:Male; D008458:Measles Vaccine / Q000276:immunology*
chemical_list: D000914:Antibodies, Viral; D000956:Antigens, Viral; D008458:Measles Vaccine