CB-201(Crescendo)

The human hybridoma cell line CB-201 has been obtained from a fusion of fetal spleen lymphocytes (31st gestational week) with heteromyeloma cells. The IgM (lambda) secreted was found to bind to lipid A, whereas other endogenous and exogenous antigens were not recognized. The CB-201 antibody is encoded by the unmutated VH6 gene recombined with DN4 and JH3 elements and a V lambda subgroup 1 gene. Therefore, a VH gene, which was previously described to be over-represented in the fetal repertoire and to be expressed in autoantibody-producing B cells, may encode an anti-bacterial specificity.

Cabbage hybrids, which clearly present heterosis vigor, are widely used in agricultural production. We compared two S5 haplotype (Class II) cabbage inbred-lines 87-534 and 94-182: the former is highly SC while the latter is highly SI; sequence analysis of SI-related genes including SCR, SRK, ARC1, THL1, and MLPK indicates the some SNPs in ARC1 and SRK of 87-534; semi-quantitative analysis indicated that the SI-related genes were transcribed normally from DNA to mRNA. To unravel the genetic basis of SC, we performed whole-genome mapping of the quantitative trait loci (QTLs) governing self-compatibility using an F₂ population derived from 87-534 × 96-100. Eight QTLs were detected, and high contribution rates (CRs) were observed for three QTLs: qSC7.2 (54.8%), qSC9.1 (14.1%) and qSC5.1 (11.2%). 06-88 (CB201 × 96-100) yielded an excellent hybrid. However, F₁ seeds cannot be produced at the anthesis stage because the parents share the same S-haplotype (S57, class I). To overcome crossing incompatibility, we performed rapid introgression of the self-compatibility trait from 87-534 to 96-100 using two self-compatibility-QTL-specific markers, BoID0709 and BoID0992, as well as 36 genome-wide markers that were evenly distributed along nine chromosomes for background analysis in recurrent back-crossing (BC). The transfer process showed that the proportion of recurrent parent genome (PRPG) in BC₄F₁ was greater than 94%, and the ratio of individual SC plants in BC₄F₁ reached 100%. The newly created line, which was designated SC96-100 and exhibited both agronomic traits that were similar to those of 96-100 and a compatibility index (CI) greater than 5.0, was successfully used in the production of the commercial hybrid 06-88. The study herein provides new insight into the genetic basis of self-compatibility in cabbage and facilitates cabbage breeding using SC lines in the male-sterile (MS) system.