Abstract W MP118: In Situ B-cell Clonal Expansion and Recombinant Antibody Construction in Human Cerebral Cavernous Malformation
Background: We had demonstrated immunocompetent cell infiltration and oligoclonal immune response in human cerebral cavernous malformation (CCM) lesions. However, T- and B- cell crosstalk, relationship between antibody and complement, and IgG repertoire in CCMs remain unknown. We hypothesize the synergetic role of T and B cells, antibody- and complement- mediated cytotoxicity, antigen-driven B cell clonal expansion, contributing to the CCM pathogenesis.
Methods: This study enrolled a total of 10 patients with CCMs. B- and T- cells were immunostained in two excised human CCM lesion specimens. IgG and complement protein membrane attack complex (MAC) was co-localized in six other CCM lesions by immunofluorescence. Plasma cells in two CCM lesions were laser-microdissected, in which IgG heavy (H) and light (L) chain variable (V) region were amplified via nested PCR, cloned, sequenced, and aligned to a database IMGT®. The over-expressed IgGHV and IgGLV were used to construct the recombinant antibodies (r-abs).
Results: In CCM lesions, T- and B- cells were clustered and co-localized, and plasma cells were clustered. IgG and MAC was co-localized in CCMs. IgG repertoire showed in situ B cell clonal expansion and ongoing somatic mutation. Four r-abs were constructed from clonally expanded plasma cells in CCM lesions.
Conclusions: we showed the role of immunity in CCM pathogenesis via T- and B- cell crosstalk, antibody- and complement- mediated cytotoxicity, and clonal expansion. We gave the first demonstration that oligoclonal response is antigen-driven. The first synthesized r-abs will be used to identify disease relevant antigens. This would clarify the relationship of immune response to CCM lesion development, and may open novel therapeutic venues in CCMs.
Author Disclosures: C. Shi: None. R. Shenkar: None. A. Kinloch: None. N. Zheng: None. S.G. Henderson: None. M. Shaaya: None. A.S. Chong: None. M.R. Clark: None. P.C. Wilson: None. I.A. Awad: None.
This research has received full or partial funding support from the American Heart Association, National Center.
- © 2014 by American Heart Association, Inc.