Figure 2.

CEACAM receptors interact specifically with Opa_CEA proteins expressed in Gc. Bacteria expressing OpaD, Opa₅₀, or Opa₆₀, or Opa− Gc, were incubated with NCCM1 (A) or NCCM3 (B), and samples were centrifuged for pellet (P) and supernatant (S) immunoblot assessment. Folded Opa proteins migrate at a lower apparent molecular weight than unfolded Opa proteins^{46, 47}; therefore, the two bands correspond to folded (lower band) and unfolded (upper band) protein in the Opa immunoblots. *Higher molecular weight bands in the Gc pellet samples of the CEACAM blots indicate nonspecific CEACAM antibody reactivity with antigens on the surface of Gc. The intensity of NCCM pellet bands were quantified with ImageJ and plotted for each Opa – NCCM combination (C).