Key result
Genetic deficiency of B cells or class-switched immunoglobulins, and adoptive transfer of IgG, did not alter blood pressure or end-organ damage in experimental mouse models of hypertension.
Why the study?
Elevated serum immunoglobulins are associated with hypertension, but whether immunoglobulins and B cells play a causal role in hypertension pathology remained unclear.
Does B-cell deficiency or lack of class-switched high-affinity immunoglobulins prevent the development of hypertension and end-organ damage in experimental mouse models?
Does B-cell deficiency or lack of class-switched high-affinity immunoglobulins prevent the development of hypertension and end-organ damage in experimental mouse models?
These preclinical findings suggest that elevated immunoglobulins observed in hypertension act as a bystander reflective of immune activation rather than playing a causal role in disease pathology.
AIMS: Elevated serum immunoglobulins have been associated with experimental and human hypertension for decades but whether immunoglobulins and B cells play a causal role in hypertension pathology is unclear. In this study, we sought to determine the role of B cells and high-affinity class-switched immunoglobulins on hypertension and hypertensive end-organ damage to determine if they might represent viable therapeutic targets for this disease. METHODS AND RESULTS: We purified serum immunoglobulin G (IgG) from mice exposed to vehicle or angiotensin (Ang) II to induce hypertension and adoptively transferred these to wild type (WT) recipient mice receiving a subpressor dose of Ang II. We found that transfer of IgG from hypertensive animals does not affect blood pressure, endothelial function, renal inflammation, albuminuria, or T cell-derived cytokine production compared with transfer of IgG from vehicle infused animals. As an alternative approach to investigate the role of high-affinity, class-switched immunoglobulins, we studied mice with genetic deletion of activation-induced deaminase (Aicda-/-). These mice have elevated levels of IgM but virtual absence of class-switched immunoglobulins such as IgG subclasses and IgA. Neither male nor female Aicda-/- mice were protected from Ang II-induced hypertension and renal/vascular damage. To determine if IgM or non-immunoglobulin-dependent innate functions of B cells play a role in hypertension, we studied mice with severe global B-cell deficiency due to deletion of the membrane exon of the IgM heavy chain (µMT-/-). µMT-/- mice were also not protected from hypertension or end-organ damage induced by Ang II infusion or deoxycorticosterone acetate-salt treatment. CONCLUSIONS: These results suggest that B cells and serum immunoglobulins do not play a causal role in hypertension pathology.
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Chen et al. (2020) studied Hypertension. B-cell deficiency, Aicda deletion, and IgG adoptive transfer vs. Wild-type littermates or vehicle IgG transfer was evaluated on Blood pressure and hypertensive end-organ damage (endothelial function, renal inflammation, albuminuria). Genetic deficiency of B cells or class-switched immunoglobulins, and adoptive transfer of IgG, did not alter blood pressure or end-organ damage in experimental mouse models of hypertension.
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