Age-dependent effects of repeated immunization with a first generation adenovirus vector on the immune response and transgene expression in young and old rats.
We evaluated the kinetics of transgene expression and humoral and cellular immune responses against viral antigens and the product of the reporter gene LacZ in young (4 months) and old (20 months) Wistar rats. Animals received the intramuscular injection of a recombinant E1-deleted human type 5 adenovirus encoding beta-gal (Ad-LacZ) on days 0 and 30. The transgene expression evaluated on day 2 after infection revealed a significantly higher beta-gal activity in young than in old animals (1.9-fold increase, p<0.05). beta-gal expression decreased on day 6, and on day 15 transgene activity was undetectable in muscles from both groups. Ad-LacZ inoculation was repeated on day 30 in both animal groups. However, after the second adenovirus administration, no increase in beta-gal activity was observed. Humoral and cellular immune responses, evaluated after the first and second Ad-LacZ injection, developed with similar kinetics in young and old rats. In particular, the antigen specific antibodies were able to kill adenovirus-infected tumor cells in both complement-dependent cytotoxicity (CDC) and antibody-mediated cell-dependent cytotoxicity (ADCC) assays. Lymphocyte proliferation in response to the in vitro stimulation with specific antigens was significantly lower in old than in young animals whereas no difference was found in cytotoxic T lymphocyte activity against adenovirus-infected tumor cells. Our results demonstrate that repeated immunization with AdCMV.LacZ induces minor age-related differences in immune response which precludes gene expression both in young and old animals.
Massari
Irene
I
Laboratorio di Patologia Vascolare, Istituto Dermopatico dell' Immacolata, Istituto di Ricovero e Cura a Carattere Scientifico, Via dei Monti di Creta 104, 00167 Rome, Italy.
Donnini
Alessia
A
Argentati
Katy
K
Straino
Stefania
S
Mangoni
Antonella
A
Gaetano
Carlo
C
Viticchi
Claudio
C
Capogrossi
Maurizio
M
Provinciali
Mauro
M
D000260:Adenoviruses, Human / Q000276:immunology*; D000375:Aging / Q000276:immunology*; D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D000920:Antibody-Dependent Cell Cytotoxicity; D002455:Cell Division; D003165:Complement System Proteins / Q000276:immunology; D003601:Cytotoxicity Tests, Immunologic; D015870:Gene Expression; D005822:Genetic Vectors / Q000276:immunology*; D007114:Immunization; D007763:Lac Operon; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D013154:Spleen / Q000166:cytology; D013602:T-Lymphocytes, Cytotoxic / Q000166:cytology / Q000276:immunology; D019076:Transgenes
D000914:Antibodies, Viral; D003165:Complement System Proteins