Cytotoxic T-lymphocyte precursor frequencies in BALB/c mice after acute respiratory syncytial virus (RSV) infection or immunization with a formalin-inactivated RSV vaccine.
A better understanding of the immune response to live and formalin-inactivated respiratory syncytial virus (RSV) is important for developing nonlive vaccines. In this study, major histocompatibility complex (MHC) class I- and II-restricted, RSV-specific cytotoxic T-lymphocyte precursor (CTLp) frequencies were determined in bronchoalveolar lavage (BAL) samples and spleen lymphocytes of BALB/c mice intranasally infected with live RSV or intramuscularly inoculated with formalin-inactivated RSV (FI-RSV). After RSV infection, both class I- and class II-restricted CTLps were detected by day 4 or 5 postinfection (p.i.). Peak CTLp frequencies were detected by day 7 p.i. The class II-restricted CTLp frequencies in the BAL following RSV infection were less than class I-restricted CTLp frequencies through day 14 p.i., during which class I-restricted CTLp frequencies remained elevated, but then declined by 48 days p.i. The frequencies of class II-restricted CTLps in the BAL were 2- to 10-fold less than those of class I-restricted CTLps. For spleen cells, frequencies of both MHC class I- and II-restricted CTLps to live RSV were similar. In contrast, class II-restricted CTLps predominated in FI-RSV-vaccinated mice. RSV challenge of vaccinated mice resulted in an increase in the frequency of class I-restricted CTLps at day 3 p.i. but did not enhance class II-restricted CTLp frequencies. These studies demonstrate differences in the CTLp response to live RSV infection compared with FI-RSV immunization and help define possible mechanisms of enhanced disease after FI-RSV immunization. In addition, these studies provide a quantitative means to address potential vaccine candidates by examining both MHC class I- and II-restricted CTLp frequencies.
Tripp
R A
RA
Division of Viral and Rickettsial Diseases, National Center of Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA.
Anderson
L J
LJ
D000818:Animals; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology / Q000276:immunology; D005260:Female; D005557:Formaldehyde; D015395:Histocompatibility Antigens Class I; D000949:Histocompatibility Antigens Class II; D007114:Immunization; D051379:Mice; D008807:Mice, Inbred BALB C; D018357:Respiratory Syncytial Virus Infections / Q000276:immunology* / Q000473:pathology / Q000517:prevention & control; D012136:Respiratory Syncytial Viruses / Q000276:immunology* / Q000472:pathogenicity; D013154:Spleen / Q000276:immunology / Q000473:pathology; D013234:Stem Cells / Q000276:immunology / Q000473:pathology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology* / Q000473:pathology; D013997:Time Factors; D015164:Vaccines, Inactivated / Q000494:pharmacology; D014765:Viral Vaccines / Q000494:pharmacology*
D015395:Histocompatibility Antigens Class I; D000949:Histocompatibility Antigens Class II; D015164:Vaccines, Inactivated; D014765:Viral Vaccines; D005557:Formaldehyde