ABSTRACT
Seasonal influenza vaccination elicits a diminished adaptive immune response in the elderly, and the mechanisms of immunosenescence are not fully understood. Using Ig-Seq, we found a marked increase with age in the prevalence of cross-reactive (CR) serum antibodies that recognize both the H1N1 (vaccine-H1) and H3N2 (vaccine-H3) components of an egg-produced split influenza vaccine. CR antibodies accounted for 73% ± 18% of the serum vaccine responses in a cohort of elderly donors, 65% ± 15% in late middle-aged donors, and only 13% ± 5% in persons under 35 years of age. The antibody response to non-HA antigens was boosted by vaccination. Recombinant expression of 19 vaccine-H1+H3 CR serum monoclonal antibodies (s-mAbs) revealed that they predominantly bound to non-HA influenza proteins. A sizable fraction of vaccine-H1+H3 CR s-mAbs recognized with high affinity the sulfated glycans, in particular sulfated type 2 N-acetyllactosamine (Galß1-4GalNAcß), which is found on egg-produced proteins and thus unlikely to contribute to protection against influenza infection in humans. Antibodies against sulfated glycans in egg-produced vaccine had been identified in animals but were not previously characterized in humans. Collectively, our results provide a quantitative basis for how repeated exposure to split influenza vaccine correlates with unintended focusing of serum antibody responses to non-HA antigens that may result in suboptimal immunity against influenza.
Subject(s)
Antibodies, Viral/biosynthesis , Influenza Vaccines/immunology , Influenza, Human/immunology , Viral Proteins/immunology , Adult , Age Factors , Aged , Animals , Antibodies, Monoclonal/immunology , Antibodies, Viral/blood , Cohort Studies , Cross Reactions , Eggs/analysis , Humans , Immunoglobulin G/biosynthesis , Immunoglobulin G/blood , Influenza A Virus, H1N1 Subtype/immunology , Influenza A Virus, H3N2 Subtype/immunology , Influenza, Human/prevention & control , Influenza, Human/virology , Middle Aged , Polysaccharides/immunology , VaccinationABSTRACT
Genetic and epidemiological studies have found that variations in the amyloid precursor protein (APP) and the apoliopoprotein E (APOE) genes represent major modifiers of the progressive neurodegeneration in Alzheimer's disease (AD). An extra copy of or gain-of-function mutations in APP correlate with early onset AD. Compared to the other variants (APOE2 and APOE3), the ε4 allele of APOE (APOE4) hastens and exacerbates early and late onset forms of AD. Convenient in vivo models to study how APP and APOE4 interact at the cellular and molecular level to influence neurodegeneration are lacking. Here, we show that the nematode C. elegans can model important aspects of AD including age-related, patterned neurodegeneration that is exacerbated by APOE4 Specifically, we found that APOE4, but not APOE3, acts with APP to hasten and expand the pattern of cholinergic neurodegeneration caused by APP Molecular mechanisms underlying how APP and APOE4 synergize to kill some neurons while leaving others unaffected may be uncovered using this convenient worm model of neurodegeneration.
