Figure 3: Comparison of VSN Ca2+ responses to stimulation with MHC-dependent and –independent peptides.

(a,b) Examples of Ca2+ responses from single VSNs to the MHC-independent MHC motif peptide TRVLNLGPI, its longer versions IDQTRVLNLGPI and SGNFIDQTRVLNLGPITR, and the MHC-dependent peptide SIINFEKL using saturating concentrations (10−11 M). Arrows indicate the time points at which stimulus application was turned on. (c) Summary of response profiles from VSNs that were stimulated successively with TRVLNLGPI, IDQTRVLNLGPI, SGNFIDQTRVLNLGPITR and SIINFEKL. The results from repeated stimulations were identical. Note that there was no overlap between VSNs activated by TRVLNLGPI or SIINFEKL.