Antitoxin component of a type II type II toxin-antitoxin (TA) system. Neutralizes the toxic effect of cognate toxin HipA. Represses the hipBA operon promoter (By similarity). Homodimer. Forms a HipA(2)HipB(2) heterotetramer which can interact with DNA. This complex also blocks the toxic activity of HipA (By similarity). Deletion of the hipB-hipA operon has no effect on virulence in mouse infection; the disrupted strain is as virulent as wild-type.