Sera antibodies (used in dilution of 1 1:1000) bound to epitopes were recognized by anti-human IgG secondary antibodies conjugated with AP. lung epithelial cell collection. In vitro, a significant induction of IL-6 by conjugate was observed, thereby we postulate that this new 131KKGIK135 epitope possesses immunostimulating properties suggesting possibility of its use in a vaccine against species, for example, and its cross-linking antigens [3,4,9,11,19,20]. In addition, immunoglobulin G (IgG) antibodies against CD can be found in the umbilical cord blood [21]. Newborns have natural passive immunity, which is a result of an active transfer of these immunoglobulins through the placenta from your mother to the fetus. Asymptomatic carriage means CD colonization with no signs of the disease. These patients have higher level of specific anti-CD IgG and IgA antibodies [2,9,22]. The group of asymptomatic service providers includes 5C15% of healthy adults, of which 57% are people living in long-term 7-Dehydrocholesterol care facilities [15]. Patients infected with CD who did not develop a sufficiently strong humoral anti-toxin pre-infection response show symptoms of the disease. This group can be divided into two subgroups: those who experienced only 7-Dehydrocholesterol one, acute episode of CDI and recovered (convalescents), and those who suffer from relapses [3]. Compared with asymptomatic carriage, both groups, during acute CDI and relapse, demonstrate weaker immune response that manifests itself mainly by lower levels of anti-CD toxin IgG antibodies. However, in the group of first acute CDI episode, the immune response against CD toxins is still stronger than during the relapses [3,9,23,24]. To sum up, it appears that high levels of serum IgA and IgG antibodies against CD toxins, in particular IgG1 and IgG2 type, protect against CDI [3,11]. The acknowledgement of CD toxins and non-toxic CD antigens by human immune system have an impact around the course of the infection and bacteria survival [25]. Non-toxic antigens include cell wall proteins (CWPs), like S-layer proteins (SLPs), that 7-Dehydrocholesterol are responsible for adhesion to the host intestine epithelial cells, as well as for other functions crucial for bacterial virulence [7,26]. CWPs are necessary for effective colonization, leading to development of the disease [7,25,27,28,29]. Drudy et al. noticed that anti-SLP IgM level of antibodies in the sera of relapsing patients was significantly lesser on the third day of contamination as compared to patients having the first episode of CDI. Based on these results, the authors concluded that the presence of specific anti-SLP IgM antibodies in patient serum is associated with a decreased risk of CDI-associated diarrhea [28]. Mulligan 7-Dehydrocholesterol et al. emphasized the importance of IgA antibodies detected in patients sera, both against toxins and non-toxic antigens [30]. Surface proteins can activate and modulate the immune response. For example, CD SLPs induce the production Rptor of proinflammatory cytokines (IL-1, IL-6), as well as anti-inflammatory and regulatory IL-10 by monocytes [31]. The use of CD non-toxin antigens gives an advantage in fighting the infection since they are often implicated in the colonization step which is the first stage of contamination. Taking all of the above into consideration, the present study was intended to indicate new immunoreactive proteins (protein M24) which can constitute the potential components of peptide vaccine. Another goal was to map the epitopes of peptidase M24 using bioinformatics methods and identify a candidate for an epitope-based peptide vaccine. Twenty-one peptides were synthesized using PEPSCAN method followed by the evaluation of their immunoreactivity using Enzyme-Linked Immunosorbent Assay (ELISA). Three groups of sera: sera from patients during first CDI episode, healthy individuals, and umbilical cord blood sera were employed in the test. The 131KKGIK135 peptide conjugated with a bovine serum albumin carrier protein (BSA) was examined for its immunostimulatory.