Development of a high-performance affinity chromatography-based method to study the biological interaction between whole micro-organisms and target proteins.

AIMS: The bacteria-host molecular cross-talk is the matter of primary importance both in pathogenesis and in commensalism. Principally based on immunological methods, the methodologies commonly utilized for these studies are laborious and require specific antibodies. Here, we developed a new high-performance affinity chromatography (HPAC)-based approach that allows a direct measure of the interaction between whole bacterial cells and host molecules. METHODS AND RESULTS: Bifidobacterium lactis BI07 cells immobilized on amino-derivatized silica beads were utilized as stationary phase in a high-performance affinity chromatography approach. The analytes plasminogen, collagen I and collagen IV were injected, and interactions were evaluated by the insertion in an HPLC system with UV detection. According to our data, Bif. lactis BI07 is capable of interacting with plasminogen, while it does not exhibit any binding activity to collagen I and IV. CONCLUSIONS: In this study, we implemented a high-performance affinity chromatography-based method to characterize the biological interaction between whole micro-organisms and target proteins. SIGNIFICANCE AND IMPACT OF THE STUDY: With respect to the approaches commonly utilized to study the interaction between bacteria and host proteins, this HPAC-based approach is fast and cheaper than other methods and allows a direct measure of the interaction between bacterial cells and target molecules.

Prognostic role of preoperative nutritional and immunological assessment in the surgical patient.

The utilization of delayed hypersensitivity response (DHR) for the identification of high-risk patients with regard to postoperative septic complications is still discussed. The aim of this study was to clarify how much DHR may improve the prognostic capacity of nutritional assessment (NA). Nutritional and immunological evaluations were performed at admission on 405 patients undergoing elective general surgical procedures. Subjects with serum albumin less than or equal to 3.0 g/dl or total iron-binding capacity less than or equal to 220 micrograms/dl or weight loss greater than or equal to 10% with respect to usual body weight were classified as malnourished. DHR was assessed by performing skin tests with four recall antigens: PPD, candida, trichophyton, sk-sd. The incidence of postoperative complications resulted higher among the 187 malnourished patients (31.0%) than in the 218 well-nourished ones (14.2%) (p less than 0.001), and among the 213 anergic patients (29.6%) than in the 192 normal responders (13.5%) (p less than 0.001). To determine how much skin tests may improve the prognostic ability of NA, the relationship between DHR and postoperative complications was also studied in the malnourished and in the well-nourished patients, separately. In the malnourished group, the patients with an impairment of DHR had a higher incidence of postoperative infections than normal responders (p less than 0.05). In the well-nourished group, no significant differences were found between anergic patients and normal responders. In our study, DHR slightly improved the prognostic capacity of NA. Therefore, the first approach to identify the high-risk patients seems to be the unexpensive, quick and available determination of nutritional status.

Causes of anergy in the surgical patient and its relationship to postoperative sepsis.

Between June 1981 and June 1983 the delayed hypersensitivity response (DHR) was studied in 401 patients considered for major surgical procedure: 320 of these patients underwent surgery. The incidence of sepsis and postoperative mortality was higher in anergic and relative anergic patients than in normal responders (p<0.001). To evaluate whether DHR depression in cancer patients was due to the direct effect of cancer or to tumour-linked malnutrition, the 401 patients were divided into 4 groups: 1) 140 malnourished cancer patients, 2) 51 malnourished non-cancer patients, 3) 120 well-nourished cancer patients and 4) 90 well-nourished non-cancer patients. The mean age was not significantly different for the 4 groups. The results showed a relationship between DHR and nutritional status (p<0.001). The tumour-related DHR impairment disappeared when the cancer and non-cancer patient groups were homogeneous with regard to their nutritional status. Therefore, the tumour was able to determine the DHR depression because of the cancer-linked malnutrition. We did not observe any relationship between local extension of the tumour and lymph node involvement and DHR depression. In 90 well-nourished non-cancer patients the relation between DHR and age was investigated. The incidence of anergy and relative anergy was higher in patients over 59 years than in patients under 60 years (p<0.001).