ADAM28 overexpression but not control lentivirus infection induced CD19‐deficient MZP (CD21hiIgMhiCD1dhiCD23+IgDhi) to produce MZ B cells (CD21hiIgMhiCD1dhiCD23−IgDlo) (Fig. 5F, G and Fig. S5). This evidence concerns the gene CD19 and lentivirus infection.