例句與用法

1. At present , in an attempt to stimulate specific antitumor immunity , experimental models and clinical studies are currently evaluating the potent antigen - presenting capacity of dc combined with single or multiple tumor antigen epitopes . however , there are several problems in utilizing pulsing dc with synthetic immunodominant peptides from identified antigens . 1 ) the potential induction of tolerance ; 2 ) the need to determine the patient ' s hla haplotype , the limitation of therapy to patients whose tumors express defined specific tumor antigens in the context of the correct hla phenotype , the unavailability of peptides for all hla haplotypes ; 3 ) the lack of cd4 help cell - related epitopes for most antigens ; and 4 ) the ctl resulting from such protocols have a good in vitro capacity to kill peptide - pulsed target cells but only a modest capacity to kill tumor cells
   但是，學(xué)者們發(fā)現(xiàn)這一療法存在著如下的缺陷：單一ctl表位抗原肽的應(yīng)用其抗腫瘤作用弱于多種腫瘤抗原的聯(lián)合應(yīng)用，且有誘導(dǎo)免疫耐受的潛在危險(xiǎn)，有時(shí)反而會(huì)促進(jìn)腫瘤的生長；事先需對(duì)患者的hla單倍型進(jìn)行鑒定，以確定ctl表位與hla單倍型是否匹配，目前尚缺乏能與所有hla單倍型相匹配的ctl表位，從而限制了這一療法的應(yīng)用；這一療法所產(chǎn)生的ctl在體外能有效殺傷經(jīng)腫瘤抗原肽共孵育過的靶細(xì)胞，但對(duì)腫瘤細(xì)胞的殺傷能力較弱：這種l表位抗原肽缺乏cd4汀h細(xì)胞相關(guān)的表位，因此，不能誘導(dǎo)有效的th細(xì)胞免疫應(yīng)答。