Analysis of cellular responses toMycoplasma mycoidessubsp.mycoidessmall colony biotype associated with control of contagious bovine pleuropneumonia

Abstract

-A better understanding of protective immune memory against contagious bovine pleuropneumonia (CBPP) is needed in order to facilitate the development of safer vaccines based on selected components of the pathogen. For this purpose, cells collected from lymph nodes draining the lungs of Mycoplasma mycoides subsp. mycoides small colony biotype (MmmSC)-infected cattle were stimulated with the pathogen in vitro and evaluated concurrently for proliferation (CFSE based method), expression of activation, memory markers and cytokine production. Direct evidence is presented for a major contribution of CD4 + T cells to the vigorous proliferative and T1 biased cytokine recall responses observed in cattle that have recovered from infection but not in animals developing the acute form of the disease. Two different phenotypes of MmmSC-specific memory CD4 were observed based on CD62L expression and proliferative capacities. Furthermore, recall proliferation of B cells also occurred but was strictly dependent on the presence of CD4. The information provided in this study will facilitate the search for MmmSC antigens that have potential for the development of subunit vaccines against CBPP.contagious bovine pleuropneumonia / Mycoplasma mycoides subsp. mycoides SC / vaccine / memory / CD4

Identification of Mycoplasma mycoides subsp. mycoides Small Colony Genes Coding for T-Cell Antigens

“…Previous work indicated that CD4 ϩ T cells make a major contribution to the vigorous T1-biased anamnestic cellular immune response observed for cattle that have recovered from infection (2,3,18). More recently, we demonstrated that MmmSC-specific memory CD4 ϩ T cells comprise two phenotypically and functionally different subsets (19).…”

“…ϩ T cells appear to be associated with resistance to infection (2,3,18), thus providing a rationale for targeting these responses in novel vaccine strategies. Ideally, subunit CBPP vaccines should elicit not only CD4…”

“…Briefly, cells collected from mediastinal lymph nodes (LN) draining the lungs of zebu cattle that completely recovered from CBPP (i.e., showing no clinical signs and healthy lungs with only limited scarring left from previous sequestra) were used in this study. LN cells from animals I9, I12, C4, and C13, which recovered from CBPP (3), also termed primed cells, showing vigorous recall proliferation of CD4 ϩ T cells and IFN-␥ production in response to whole MmmSC (18,19) were used for the screening of recombinant MmmSC proteins and peptides. Finally, LN cells were also prepared from three naïve animals for control purposes.…”

“…Upon thawing, cells were loaded with 1 M (final) carboxyfluorescein diacetate succinimidyl ester (CFSE) (Invitrogen, Cergy-Pontoise, France) as described previously (18). Proliferation is proportional to the decrease in CFSE fluorescence occurring after cell division and can be measured at the single-cell level by flow cytometry (see below).…”

Timing of activation of CD4+ memory cells as a possible marker to establish the efficacy of vaccines against contagious agalactia in sheep

“…In order to assess an effective subunit vaccine against Mycoplasma mycoides subsp. mycoides, researchers are studying molecules able to activate central and effector memory CD4 + cells, since it seems they are the most suitable peptides to be included in such vaccines (Totté et al, 2008).…”