Neisseria gonorrhoeae
"Neisseria" species including "Neisseria gonorrhoeae" (which causes gonorrhea), "Streptococcus pneumoniae", and "Haemophilus influenzae" type B all release a protease that destroys IgA. Additionally, "Blastocystis" species have been shown to have several subtypes that generate cysteine and aspartic protease enzymes which degrade human IgA.