Characterization of peripheral B- cells in aged individuals

Allison Nipper

Rush University Medical Center, Department of Immunology and Microbiology, Chicago, IL Impaired Humoral Response of Aged Individuals

• 90% of deaths from influenza occur in individuals over 65 years of age [1,2]

• Aged individuals not adequately protected by vaccination [3-5]

– Partly due to B-cell dysfunction in aging

1. W. W. Thompson , et al. Influenza Other Respi Viruses 2009;3:37--49. 2. W. W. Thompson, et al. Journal of the American Medical Association, vol. 289, no. 2, pp. 179-186, 2003. 3. S. Sasaki, et al. Journal of Clinical Investigation, vol. 121, no. 8, p. 3109–3119, 2011. 4. T. M. Govaert, et al. Journal of the American Medical Association, vol. 272, pp. 1661-1665, 1994. 5. A. Ortqvist, et al. Lancet, vol. 7351, no. 9100, pp. 399-403, 1998.

Can principles of HIV’s immune dysregulation be applied to aging B cells?

AGING HIV •Shift in B-cell subsets •Decreased production of B-cell precursors •Dysregulated B-cell TLR expression/responsiveness •Shift in B-cell subsets •Elevated expression of • Reduced expression of inhibitory molecules on B CSR molecule AID cells •Reduced BCR diversity •Dysregulation of B-cell IMMUNE DYSREGULATION co-stimulatory molecules •Poor vaccine response •Impaired BCR signaling •Poor antibody specificity •Decreased antibody affinity •Impaired isotype switching Hypothesis: mechanism underlying the observed impaired B-cell response of aged individuals is multifactorial

Dysregulation Defective BCR Increased inflammatory Disruption in subsets of inhibitory molecules signaling/synergism cytokines (IL-6)

CD22

CD72 Bregs RM BCR IL-6 CD85J TLR

B cell TLM B cell B cell

B-cell exhaustion

Impaired humoral response seen in aged individuals Inclusion Criteria

Aged Young

•>65 years old (median age 81.5) •22-45 years old (median age 28) •Reported by clinician to have no signs of •No signs of chronic illness illness •No medications known to alter (e.g.,statins, anti-inflammatories) •Recruited from Rush Alzheimer’s Disease Center and Rush University Senior Care

B-cell Subsets Disrupted in Aged Subjects

• Fewer total B cells in aged subjects (p=0.006)

• Aged subjects have significantly (p=0.024)

33.62% 24.49% fewer resting memory B cells Resting Naive Memory CD10- CD20+ 

CD21 Tissue- Activated like Memory Memory

CD27 B-Cell Phenotypic Characterization

FcRL1 CD22 FcRL2 BCR FcRL3 inhibitory CD72 molecules FcRL4 BCR by RT- Inhibitory CD85j FcRL5 qPCR molecules by flow CD305 cytometry

PD- CD40 Co- CD80 stimulatory TLR1/6 B Cell molecules TLR2 CD86 by flow TLRs cytometry by RT- TLR5 HLA-DR qPCR TLR10 TLR2/6 Expression of Inhibitory Markers in Aged Subjects

CD22-also mediates B-cell CD72-constitutively active- CD85j-can prevent signaling via clathrin- likely sets threshold of BCR isotype switching mediated endocytosis signaling

These BCR inhibitory molecules are upregulated in

HIV infection[1]

1. Moir et al. 2008 JEM. 205 (8): 1797 Expression of BCR Inhibitory Molecules TLR Response

• HIV-infected individuals have Blunted B cell TLR response

• TLR response could be impaired in B cells of aged individuals as well

Siewe et al. AIDS Res Hum Retroviruses. 2013 Oct;29(10):1353-60 Expression of TLR4 and TLR5 Decreased in Aged Subjects Role of TLR Signaling and Inflammation in Impaired B-cell Response of Aged Subjects

* * CpG DNA CpG DNA CpG DNA Antigen CD72 CD85j TLR CD22 BCR

ITIM P SHP-1

P SYK ClassCa2+ Switch RecombinationNF-κB

Class Switch AID Recombination Acknowledgements

Landay Lab Alan Landay Basile Siewe Jeff Martinson Jill Plants Kristin Bush

Clinics Rush Alzheimer’s Disease Center

Rush University Senior Care Poster 7