B Cells are not locked into making a certain class of Antibody—they always start with IgM but can switch the Antibody type if the Helper T Cell asks and encourages them to! Having a nasty cold or a gut infection and need a lot of antibodies in your snot or stool? Make IgA! Having a parasitic worm in your intestines? Make IgE! A lot of bacteria have infected a wound? Make IgG flavor one! There are a lot of virus-infected cells? Please, more IgG flavor three! (Once an Antibody class has been switched there is no going back though.)
