Pan DR TH epitope

[Catherine McIntyre]

I have managed to obtain the amino acid sequence of a PanDR TH epitope 
for the activation of T helper cells to assist in the generation of a 
CTL response in vitro. I have tried to have the peptide manufactured but 
the sequence has lower case "a" in it. Can anyone tell me what they 
mean?
The sequence is aKXVAAWTLKAAa-NH2
I presume that the "X" means that any amino acid can be inserted at this 
position?

Any thoughts would be very welcome

Thanks