@article {542681,
	title = {Cutting edge: a crucial role for B7-CD28 in transmitting T help from APC to CTL.},
	journal = {J Immunol},
	volume = {169},
	number = {8},
	year = {2002},
	month = {2002 Oct 15},
	pages = {4094-7},
	abstract = {Although APC activation via CD40-CD40L signaling plays a critical role in enabling CD4(+) T cells to provide the "help" necessary for cross-priming of naive CTL, it is unclear how this makes the APC competent for priming. We have investigated the roles of B7-1/B7-2 and their receptors [corrected] CD28/CTLA-4 in cross-priming of CD4-dependent CTL in vivo. We find that both CD28 and B7-1/B7-2 are required for CD40-activated APC to cross-prime CTL, and that priming by CD40-activated APC was prevented by blockade of CD28. Conversely, augmenting CD28 signals with an agonistic Ab bypassed the requirement for CD4(+) T help or CD40 activation. Interestingly, blockade of the negative regulatory B7 receptor CTLA-4 failed to prime CTL in the absence of T help. These results support a model in which activation-induced up-regulation of B7 molecules on APC leads to increased CD28 signaling and a commitment to cross-priming of CD4-dependent CTL.},
	keywords = {Animals, Antigen-Presenting Cells, Antigens, CD, Antigens, CD28, Antigens, CD80, Antigens, CD86, Cell Line, Cytotoxicity, Immunologic, Lymphocyte Activation, Membrane Glycoproteins, Mice, Mice, Inbred C57BL, Mice, Knockout, T-Lymphocytes, Cytotoxic, T-Lymphocytes, Helper-Inducer},
	issn = {0022-1767},
	author = {Prilliman, Kiley R and Lemmens, Edward E and Palioungas, Georgia and Wolfe, Thomas G and Allison, James P and Sharpe, Arlene H and Schoenberger, Stephen P}
}
