Illumina offers various read length options...
We offer primer kits that take advantage of Illumina's different paired-end read (PER) length options. Depending on the PER length, you will be able to see the CDR1 through the CDR3 regions or just the CDR3 region.
Would you like 100, 150, or 250 paired-end reads?
Would you like to read more about the different paired-end read options?
Read more about 100 PER vs. 250 PER.