Table 1:

Effects of IgM-deficiency on humoral immunity in mice

Biological Process	Effect of IgM deficiency	Reference
B cell subset development	Increased numbers CD5+ B-1 cells in PerC and spleen	Boes et al. 1998
	Increased numbers CD5+ CD21lo CD23− CD43- anergic B cells in PerC and spleen with enhanced turnover	Nguyen et al. 2015
	Reduced pre-B cell development and bone marrow B cell output	Nguyen et al. 2015
	Abnormal spleen development with increased marginal zone B cells Increased BCR signaling	Boes et al. 1998 Nguyen et al. 2015 Tsiantoulas D. et al. 2017
BCR-repertoire	Altered VH usage in peripheral B cells	Nguyen et al. 2015
	Increased auto-antibody production: anti-dsDNA; anti-histone; ANA.	Boes et al. 2000; Ehrenstein et al. 2000 Nguyen et al. 2015
	Enhanced development of glomerulonephritis and other signs of antibody-mediated autoimmune disease	Boes et al. 2000 Ehrenstein et al. 2000
T-independent humoral immunity	No effect on total IgG, but enhanced IgG2a and reduced IgG2b responses to NP-Ficoll (1, 10 and 100 μg) immunization. Enhanced IgG 1, 2a, 2b and 3 responses to NP-Ficoll (5μg) to all IgG subclasses	Boes et al. 1998 Ehrenstein et al. 2000
T-dependent humoral immunity	Reduced IgG responses to low (1μg) but not higher (10 and 100 μg) NP-KLH immunization. Reduced IgG1 primary and secondary responses to NP-KLH (50μg). Delayed responses to NP-CG and phOx-CG immunization. Reduced affinity maturation. Normal secondary responses	Boes et al. 1998 Ehrenstein et al. 2000
	Reduced IgG1 and IgG2a responses to influenza infection Reduced IgG2a and IgG2b responses to influenza infection	Baumgarth et al. 2000; Nguyen et al. 2017 Kopf M et al. 2002