Date Published: March 25, 2013
Publisher: Impact Journals LLC
Author(s): Raj K. Kurupati, Senthil Kannan, Xiang, Zhi Xiang, Susan Doyle, Sarah Ratcliffe, Kenneth E. Schmader, Hildegund CJ Ertl.
Antibody and B cell responses to influenza A viruses were measured over a period of 2 months in 30 aged and 15 middle-aged individuals following vaccination with the 2011/12 trivalent inactivated influenza vaccine by micro-neutralization assays, ELISAs, ELISpot assays and cell surface staining with lineage-defining antibodies followed by multicolor flow cytometry. Both cohorts developed comparable antibody responses to the H3N2 virus of the vaccine while responses to the H1N1 virus were compromised in the aged. ELISpot assays of peripheral blood mononuclear cells (PBMCs) gave comparable results for the two cohorts. Analysis by flow cytometry upon staining of CD19+IgD-CD20- PBMCs with antibodies to CD27 and CD38 showed markedly reduced increases of such cells following vaccination in the aged. Additional analysis of cells from a subset of 10 younger and 10 aged individuals indicated that in the aged a portion of IgG producing cells lose expression of CD27 and reduce expression of CD38.
Worldwide, the aged constitute an increasingly large and challenging segment of the human population. In the US, approximately 13% of the population is over 65 years of age and this number is projected to increase to 20% of the population by 2050 (US Census Bureau). Diseases and disabilities vary widely among older individuals, a principle of gerontology known as aged heterogeneity [1, 2], which ranges from very fit individuals to unhealthy and functionally impaired individuals. During aging immune responses decline in a process referred to as immunoscenescence. Accordingly, the aged are disproportionally affected by infectious diseases and respond poorly to vaccination.
Here we tested acute B cell responses following TIV vaccination given in winter and spring of 2011/12 to cohorts of aged and middle-aged human subjects residing in the Triangle area of North Carolina. The study was undertaken to compare antibody and B cell responses of the two cohorts with regard to magnitude and kinetics of responses using three complementary assay systems.