Table I.

V_H gene somatic mutation among NP-specific B cells in blood and spleen

Daya	Tissue	PCR+ b	VH186.2c	Mutation (average)d	Germline	Position 33
					%	% Y → L
7	spleen	21/45	16/21	1.8	25	0
	blood	22/35	21/22	0.1	95	5
10	spleen	55/80	50/55	2.7	12	50
	blood	54/188	45/54	1.2	47	37
12	spleen	ND	ND	ND	ND	ND
	blood	27/40	24/27	2.4	33	58
14	spleen	35/80	30/35	4.4	3	67
	blood	37/97	29/37	2.3	7	48
28	spleen	43/60	29/43	5.8	7	45
	blood	28/45	21/28	4.4	28	48

^aMice were killed at the indicated times after immunization and individual B220⁺NP⁺IgG1⁺ cells were sorted by flow cytometry. Three to eight mice were used per experiment with samples pooled before sorting. Data are from at least two experiments per time point.

^bThe number of successful PCR amplifications of V_H186.2-Cγ1 rearrangements from single cell cDNA as a fraction of the number of reactions.

^cThe number of amplified V_H186.2-Cγ1 rearrangements confirmed to contain the unique hexamer as a fraction of all sequences.

^dAverage mutation frequency, percent germline sequences, and percent of sequences containing tryptophan to leucine exchange at V_H position 33 are for all V_H186.2 sequences recovered.