Because a limited number of Tfh cells reside the germinal center , only highly competitive B cells stably conjugate with Tfh cells .
Because a limited number of Tfh cells reside the germinal center , only highly competitive B cells stably thus receive T cell - dependent survival signals .
Because a limited number of Tfh cells reside the germinal center , only highly competitive B cells stably conjugate with Tfh cells and thus receive T cell - dependent survival signals .