To test whether this was also true for VapB and VapN, we added rVapA, rVapB, or rVapN to macrophages, or we added bafilomycin A1 (BafA1), which is a potent inhibitor of the lysosome-acidifying ATPase (33), and quantified LT accumulation in the absence of an infection. The gene discussed is VAPB; the disease is infection.