Svensson M, Johansson C, Wick M J
Department of Cell and Molecular Biology, Section for Immunology, Lund University, Lund, Sweden.
Infect Immun. 2000 Nov;68(11):6311-20. doi: 10.1128/IAI.68.11.6311-6320.2000.
Murine bone marrow-derived dendritic cells (DC) can phagocytose and process Salmonella enterica serovar Typhimurium for peptide presentation on major histocompatibility complex class I (MHC-I) and MHC-II molecules. To investigate if a serovar Typhimurium encounter with DC induces maturation and downregulates their ability to present antigens from subsequently encountered bacteria, DC were pulsed with serovar Typhimurium 24 h prior to coincubating with Escherichia coli expressing the model antigen Crl-OVA. Quantitating presentation of OVA epitopes contained within Crl-OVA showed that Salmonella-pulsed DC had a reduced capacity to process Crl-OVA-expressing E. coli for OVA(257-264)/K(b) and OVA(265-277)/I-A(b) presentation. In addition, time course studies of DC pulsed with Crl-OVA-expressing serovar Typhimurium showed that OVA(257-264)/K(b) complexes could stimulate CD8OVA T-hybridoma cells for <24 h following a bacterial pulse, while OVA(265-277)/I-A(b) complexes could stimulate OT4H T-hybridoma cells for >24 but <48 h. The phoP-phoQ virulence locus of serovar Typhimurium also influenced the ability of DC to process Crl-OVA-expressing serovar Typhimurium for OVA(265-277)/I-A(b) presentation but not for OVA(257-264)/K(b) presentation. Furthermore, pulsing of DC with serovar Typhimurium followed by incubation for 24 or 48 h altered surface expression of MHC-I, MHC-II, CD40, CD54, CD80, and CD86, generating a DC population with a uniform, high expression level of these molecules. Finally, neither the serovar Typhimurium phoP-phoQ locus nor lipopolysaccharides (LPS) containing lipid A modifications purified from phoP mutant strains had a different effect on DC maturation from that of wild-type serovar Typhimurium or purified wild-type LPS. Thus, these data show that Salmonella or Salmonella LPS induces maturation of DC and that this process is not altered by the Salmonella phoP virulence locus. However, phoP did influence OVA(265-277)/I-A(b) presentation by DC infected with Crl-OVA-expressing serovar Typhimurium when quantitated after 2 h of bacterial infection.
小鼠骨髓来源的树突状细胞（DC）能够吞噬并处理鼠伤寒沙门氏菌，以便在主要组织相容性复合体I类（MHC-I）和MHC-II分子上呈递肽段。为了研究鼠伤寒沙门氏菌与DC的相遇是否会诱导DC成熟并下调其呈递后续遇到细菌抗原的能力，在与表达模型抗原Crl-OVA的大肠杆菌共同孵育前24小时，用鼠伤寒沙门氏菌刺激DC。对Crl-OVA中所含OVA表位的呈递进行定量分析表明，经沙门氏菌刺激的DC处理表达Crl-OVA的大肠杆菌以进行OVA(257 - 264)/K(b)和OVA(265 - 277)/I-A(b)呈递的能力降低。此外，对用表达Crl-OVA的鼠伤寒沙门氏菌刺激的DC进行时间进程研究表明，在细菌刺激后，OVA(257 - 264)/K(b)复合物刺激CD8OVA T杂交瘤细胞的时间小于24小时，而OVA(265 - 277)/I-A(b)复合物刺激OT4H T杂交瘤细胞的时间大于24小时但小于48小时。鼠伤寒沙门氏菌的phoP-phoQ毒力位点也影响DC处理表达Crl-OVA的鼠伤寒沙门氏菌以进行OVA(265 - 277)/I-A(b)呈递的能力，但不影响OVA(257 - 264)/K(b)呈递的能力。此外，用鼠伤寒沙门氏菌刺激DC，然后孵育24或48小时，会改变MHC-I、MHC-II、CD40、CD54、CD80和CD86的表面表达，产生这些分子具有均匀高表达水平的DC群体。最后，鼠伤寒沙门氏菌的phoP-phoQ位点和从phoP突变株纯化的含有脂多糖A修饰的脂多糖（LPS）对DC成熟的影响与野生型鼠伤寒沙门氏菌或纯化的野生型LPS没有差异。因此，这些数据表明沙门氏菌或沙门氏菌LPS诱导DC成熟，并且该过程不受沙门氏菌phoP毒力位点的改变。然而，在细菌感染2小时后进行定量分析时，phoP确实影响了被表达Crl-OVA的鼠伤寒沙门氏菌感染的DC对OVA(265 - 277)/I-A(b)的呈递。
