Immunodeficiency: primary or acquired

Oral Abstract Session

DOCK8 Deficient Germinal Center B Cells Rescued by a Vav-Bcl2 Transgene Undergo Affinity Maturation

Friday, June 16
5:00 PM - 5:15 PM

DOCK8 immunodeficiency is a rare and devastating primary immunodeficiency characterized by cutaneous viral infections, recurrent sinopulmonary infections, eczema and allergic disease. It is known that DOCK8 deficiency causes a B-cell intrinsic defect in germinal center (GC) B cell survival, affecting affinity maturation.


To investigate the role of apoptosis in this decreased survival of GC cells, we crossed the DOCK8pri/pri mutation onto SWHEL mice carrying either a Fas mutation or a Vav-Bcl2 transgene and adoptively transferred 105 SWHEL transgenic B cells (from either wild-type or DOCK8pri/pri Fas mutant or VavBcl2 transgenic mice) together with mutated hen egg lysozyme covered sheep red blood cells into intact C57BL/6 mice and assessed the GC response. At day 15, single cell sorting of GC B cells allowed genetic analysis and assessment of affinity maturation.


Analysis of the GC B cells in mice receiving Fas deficient wild type or DOCK8pri/pri SWHEL B cells showed similar results to Fas sufficient cells with a loss of DOCK8pri/pri GC B cells at day 9. By contrast, DOCK8pri/pri GC B cells carrying the VavBcl2 transgene were present at both day 9 and 15 after immunization, although there remained a significant decrease in GC B cells compared to wild-type. Sequencing revealed an overall acquisition of the Y53D mutation (indicating affinity maturation) in 34% of 126 DOCK8pri/pri VavBcl2 transgenic SWHEL GC B cells sequenced, and in 45% of 114 wild-type cells. This indicates that when the VavBcl2 transgene allows for GC B cell survival, mutations in DOCK8 do not prevent affinity maturation.

Katrina L. Randall

1. John Curtin School of Medical Research, Australian National University; 2. ANU Medical School, Australian National University

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Andrew F. Ziolkowski

1. John Curtin School of Medical Research, Australian National University

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Zahra Sabouri

1. John Curtin School of Medical Research, Australian National University

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Hsei Di Law

1. John Curtin School of Medical Research, Australian National University

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Christopher C. Goodnow

1. John Curtin School of Medical Research, Australian National University; 3. Garvan Institute of Medical Research

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