Histatins are the most significant antimicrobial peptides (AMP) of saliva and there are 12 types of such AMP. Histatin molecules contain relatively high percent of histidine and tyrosine residues. This property allows to use well known from organic chemistry Pauly reaction for detection of protein bounded histidine and tyrosine residues (BHT), which are in fact characterize the summary content of all histatins in saliva. Aim of the present study was comparison of BHT with antimicrobial activity of salivary AMP fraction in patients with inflammatory diseases of upper airways (IDUA). Group of examined persons include 28 patients with different diagnoses: chronic pharyngitis (n=11), chronic tonsillitis (n=7), nasopharyngitis (n=5), pollinosis (n=5). Degree of intensity of inflammatory symptoms was estimated in balls. The algorithm of BHT analysis include following steps: freezing - thawing of saliva; removal of microparticles by centrifugation; separation of fraction lower than100 kDa; dialysis for free amino acids removal; Pauly reaction carrying out. Antimicrobial activities of saliva and its low molecular fractions were estimated towards Candida albicans cells by the spectrophotometric method with bromocresol purpur. Analysis of saliva sediments for coccoid microbiota was carried out by PCR method. Pauly reaction for histatins estimation in saliva of IDUA patients use here for the first time. The histatins levels (BHT) were significantly correlated with the intensity of inflammatory symptoms (r=0,975) and activity of low molecular salivary fraction (AMP activity) (r=0,824). The AMP activity/ BHT ratio, i.e. antimicrobial activity of histatin unit, decreased together with growth of inflammatory symptoms intensity (r=-0,944). Any considerable differences in coccoid microbiota frequency of finding at different diagnoses were not detected. The S. aureus frequency of occurrence was connected neither with inflammatory symptoms intensity (r=0,118), nor with BHT concentration (r=0,318). However S. pyogenes and S. pneumoniae frequencies of occurrence demonstrated the invert correlation towards these indexes: (r=-0,627/-0,614) and (r=-0,827/-0,864). Probably at the exacerbation forms of IDUA the S. pyogenes and S. pneumoniae growth controlled by high levels of histatins.

The contribution of the antimicrobial activity of sIgA, lactoferrin, -lactalbumin, serum albumin, and lysozyme to the total antimicrobial activity of whey was evaluated. 66 breast milk samples from healthy women aged from 23 to 45 years collected at different periods of lactation were studied. It was found that along with proceeding the lactation period, not only the total antimicrobial activity (r = 0.944) decreased, but also the activity of the low molecular weight fraction containing the sum of antimicrobial peptides (r = 0.950). The median lactoferrin level varied from 3.46 mg/ml in colostrum down to 0.94 mg/ml one year after the onset of lactation that correlated with whey activity (r = 0.616). The concentration of sIgA was peaked in the whey of colostrum (5.01 mg/ml) and significantly reduced in mature milk, remaining approximately at the same level in subsequent periods of lactation (1.0 mg/ml). Serum albumin concentration significantly decreased while proceeding through lactation period (from 5.52 to 4.68 mg/ml) and correlated with whey activity (r = 0.589). Evaluating effects of the purified -lactalbumin on C. albicans cells within the range of 520 mg/ml by spectrophotometry and microscopy showed the absence of fungicidal activity. At the same time, purified lactoferrin, IgA, lysozyme, and serum albumin demonstrated a direct fungicidal effect. The activity of the IgA preparation at a concentration relevant to the sIgA content in the whey of the first day colostrum was 50.0%, and in the whey after 12 months 31.0%; lactoferrin 26.7% and 3.4%; serum albumin 15.0% and 17.7%; lysozyme 0.1% and 1.8%. Thus, the sum of the activities of these polypeptides at concentrations typical for the first-day colostrum was 91.7%, which is comparable to the total activity of this whey 82.4%. The sum of the activities of these polypeptides, typical for 12 months of lactation, was 53.9%, and the total whey activity relevant to this period was 64.5%. Therefore, IgA and lactoferrin contribute the most significant antimicrobial activity in the whey of colostrum, whereas after 12 month-breastfeeding IgA and serum albumin become most significant.

Intense training loads alter the skin microbiome and defence mechanisms in athletes, yet adaptation profiles remain insufficiently characterised. This study evaluated the relationships between skin bacterial microbiome structure, antimicrobial activity, dermcidin levels, and acne severity in male professional hockey players compared with amateur athletes and non-athletes. One hundred men (18–57 years) were examined and allocated to six subgroups by exercise intensity and acne status. Microbiota composition was assessed by culture-based methods and MALDI-TOF identification, antimicrobial activity measured spectrophotometrically, dermcidin quantified by ELISA, and sweat proteome characterised by HPLC-MS. Staphylococcus epidermidis and Micrococcus luteus predominated in all groups. Exercise intensity, rather than acne, was the main determinant of total bacterial colonisation, which increased approximately tenfold from non-athletes to professional hockey players. In non-athletes, higher antimicrobial activity correlated with greater acne severity, whereas in professionals this relationship was absent and dermcidin levels showed an inverse association with acne severity. Proteomic analysis identified 17 polypeptides; dermcidin and prolactin-inducible protein were dominant in all groups, and calprotectin (S100-A8/A9) was detected exclusively in healthy professionals.

Object of study. The evaluation of the interaction between breast milk opportunistic microorganisms abundance and the milk whey antimicrobial activity at different periods of lactation. Materials and methods. 100 samples of breast milk from healthy breastfeeding mothers were inoculated on solid selective media, and then pure cultures of microorganisms were identified by MALDI-TOF mass spectrometry. The antimicrobial activity of the whey against a model culture of Candida albicans was evaluated by spectrophotometry. Results. 270 isolates represented by 36 species of 13 genera of opportunistic bacteria were obtained. None of the 100 samples contained opportunistic fungi. Staphylococci (7 species) and streptococci (11 species) were predominant. The most common were staphylococci S. epidermidis (70.2%) and S. aureus (20.8%), and streptococci S. mitis (27.7%) and S. oralis (21.8%). The total contamination (median) of opportunistic bacteria in the colostrum was 79 103 CFU/ml, transitional milk 4 103 CFU/ml, mature milk 5 102 CFU/ml. The antimicrobial activity of colostrum whey was 87.489.4%; transitional milk 88.2%; mature milk 63.481.9%. The total contamination had a high inverse correlation with the lactation period (r = 0.806) and a high positive correlation with the antimicrobial activity of whey (r = 0.699). Meanwhile, a significant decrease in contamination was noted after 1 month from the beginning of lactation, while a significant decrease in antimicrobial activity was observed after 8 months. Conclusions. The decrease of the breast milk contamination by opportunistic bacteria during the lactation period was found to be primary compared to the decrease of the whey antimicrobial activity. Thus, changes in the whey antimicrobial protection factors occur in response to changes of the opportunistic microbiota abundance.

The avian influenza virus (AIV) has a great pandemic potential both in animals, and in human population. For effective struggle against this virus, it is important to study the immune response against AIV, and, in particular, the features of T cell immunity. At the period of early immune response, when the activation of adaptive immunity factors has not yet occurred, the natural killers, which have both cytotoxic and immunoregulatory functions, are known to play a key role in the fight against the influenza virus. In this study, we investigated the interaction between natural killers and T helpers in the process of antiviral response. The aim of this study was to study immunoregulatory functions of NK cells in BALB/c mice vaccinated with different doses of avian influenza virus.We used a strain of mouse-adapted avian influenza virus (AIV) of the H5N2 serotype (A/duck/ Pennsylvania/10218/1984). The determination of the virus titer in the mice lung tissue was performed by infecting 10-day-old chicken embryos (SPF) with lung extracts at various decimal dilutions, followed by the immune agglutination test. Quantitative determination of natural killers and T helpers (Th) in the mice spleen tissue was carried out by flow cytometry. The amount of Th cells in mice spleens increased at low infectious dose (2.5 EID50) which is explained by active clonal expansion of this cell subpopulation. The infectious disease process ended upon complete virus elimination from the lungs. The amounts of Th cells were also increased in a group of mice infected with intermediate infectious dose (25 EID50), however, being accompanied by virus replication in lungs. When the mice were infected with a high dose of the virus (250 EID50), there was a decrease in the Th cells number versus control group of animals, whereas replication of AIV was noted throughout the entire observation period in the lung tissue.The amounts of helper T cells at high doses of viral infection could be decreased due to activation of NK cells. The activated NK cells may then eliminate exhausted helper T cells. Thus, NK cells immunoregulatory function represents an important immunological factor which keeps balance between the pathogen destruction and excessive inflammation of the lung tissue affected by the avian influenza virus.