Decreased neutrophil bactericidal activity during phagocytosis of a slime-producingStaphylococcus aureusstrain (original) (raw)
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Journal of dairy science, 1977
Intramammary infusion of saline containing .1% glycogen resulted in diapedesis of numerous leukocytes (93% polymorphonuclear leukocytes) into milk. Direct microscopic somatic cell counts of primary milk 11 h after infusion with 100 ml of either saline containing .1% glycogen, saline, distilled water, or noninfused averaged 4.17, 1.06, .05, and .10 X 10(6) cells/ml of milk. Four times more polymorphonuclear leukocytes were isolated from residual milk (6.1 X 10(9) cells) collected 11 h following infusion than from primary milk (1.5 X 10(9)). The polymorphonuclear leukocytes isolated from either the primary or residual milk collected 11 h after infusion of saline containing .1% glycogen phagocytosed Staphylococcus aureus with great avidity. Sixty-eight percent of a culture of heat-killed phosphorus-32-labeled Staphylococcus auresu (400 X 10(6)) were phagocytosed within 60 min by 25 X 10(6) polymorphonuclear leukocytes. When isolated polymorphonuclear leukocytes were incubated with live...
Journal of Clinical Microbiology
Phagocytosis by bovine polymorphonuclear granulocytes of seven capsular polysaccharide type 5 Staphylococcus aureus strains isolated from mastitis [corrected] was investigated by means of luminol-dependent chemiluminescence. Bacteria were grown on four different agar media (brain heart infusion, Columbia broth, modified staphylococcus medium 110, and skim milk) and were opsonized by normal bovine serum. When compared to growth on brain heart infusion agar, Columbia agar, and modified staphylococcus medium 110 agar, growth on skim milk agar rendered five of the strains more resistant to opsonization. The other two strains were resistant in all culture media used. Short periods of incubation in milk after growth on brain heart infusion agar did not augment resistance to phagocytosis, indicating that mere adsorption of milk components on bacteria was not responsible. The variability of the chemiluminescence response of polymorphonuclear leukocytes was pronounced among strains with each growth medium except milk. Growth on modified staphylococcus medium 110 and on milk agar favored the masking of teichoic acid, as shown by inagglutinability with rabbit antiserum. Interestingly, agglutination by a monoclonal antibody to capsular polysaccharide type 5 was optimal when bacteria were grown on skim milk agar. This suggests that capsular polysaccharide participated in the masking effect. These findings indicate that masking of the bacterial target of most of the naturally acquired opsonins present in normal bovine serum occurred when bacteria grew in the presence of milk, resulting in an increased resistance to phagocytosis by polymorphonuclear leukocytes.
Veterinary Microbiology - VET MICROBIOL, 2009
To examine the effect of parity on polymorphonuclear neutrophils (PMN) function, phagocytic and bactericidal activity of the PMN isolated from blood and milk against Staphylococcus aureus was compared between groups of 6 primiparous and 6 multiparous healthy dairy cows during early lactation using bacteriological and PMN–pathogen interaction assays. Latex-stimulated luminol-amplified chemiluminescence (CL) and viability of these PMN were also investigated. The phagocytosis and killing of S. aureus by blood were remarkably higher than those of milk PMN. Similarly, the CL and viability in blood PMN were markedly higher than in milk PMN. Both in blood and in milk the phagocytosis of S. aureus by PMN in primiparous cows was substantially higher than in multiparous cows. The killing activity of blood PMN against S. aureus was 42.3±3.4% and 23.2±1.7% in primiparous and multiparous, respectively. Milk PMN killed only 20.7±2% S. aureus in primiparous and 10.2±1.3% in multiparous cows. Blood...
Microbial Pathogenesis, 2003
Phagocytosis of bacteria by bovine polymorphonuclear neutrophils (PMN) has long been regarded as essential for host defense against mastitis infection. Complement-mediated opsonisation by complement component 3 (C3) binding is an important component of the innate immune system. We investigated the role of milk complement as an opsonin and its involvement in the phagocytosis and killing of Staphylococcus aureus isolates from cases of bovine mastitis by bovine blood PMN. We show that deposition of milk C3 component occurred on six different isolates of S. aureus and that the alternative pathway was the sole complement pathway operating in milk of uninflamed mammary gland. This deposition was shown to occur at the same location as the capsule, but not on capsular antigen. Milk complement enhanced the chemiluminescence response of PMN induced by S. aureus. Nevertheless, the association of S. aureus to cells and the overall killing of bacteria by bovine PMN were not affected by the presence of milk complement. Therefore, as all milk samples contained antibodies to capsular polysaccharide type 5 and to other surface antigens, it is likely that milk antibodies were responsible for these two phagocytic events. Results of this study suggest that the deposition of milk complement components on the surface of S. aureus does not contribute to the defence of the mammary gland against S. aureus. q
Journal of Dairy Research, 2001
Phagocytic and bactericidal activity of polymorphonuclear neutrophil leukocytes (PMN) isolated from blood and milk, against Staphylococcus aureus, was compared between groups of six healthy dairy cows in early, mid- and late lactation using a bacteriological assay. PMN were isolated from blood with a high degree of purity, but the cells isolated from milk contained variable amounts of macrophages (MΦ) and lymphocytes (L). The results were therefore calculated using the percentage PMN in order to evaluate phagocytosis and killing by PMN only. Blood PMN phagocytosed 82% Staph. aureus and milk PMN 43% on average and there was no significant difference between the different stages of lactation. The bactericidal activity of blood PMN against Staph. aureus was 36±8% in early lactation (significantly different from mid lactation, P<0·05), 64±10% in mid lactation and 53±6% in late lactation. Milk PMN killed only 6±3% Staph. aureus in early lactation (significantly different from mid lact...
Veterinary World, 2015
The present study was designed to evaluate the neutrophil dynamics in terms of the functional competence during subclinical mastitis (SCM) and clinical mastitis (CM). Materials and Methods: A total of 146 Karan fries cows were screened and were divided into three groups as control (n=12), SCM, n=12 and CM, n=12 groups on the basis of California mastitis test scoring, bacteriological evaluation, gross and morphological changes in milk and by counting milk somatic cell count (SCC). Both blood and milk polymorphonuclear neutrophils (PMNs) were isolated in the study. Phagocytic activity (PA) was studied by spectrophotometrically; neutrophil extracelluar traps (NETs) were studied by scanning electron microscopy (SEM); CD44 was quantified by flow cytometry and apoptosis was studied by fluorescent microscopy. Results: Significantly (p<0.05) higher SCC, PA was found in milk of CM cows as compared to SCM and control cows. Significantly lower (p<0.05) apoptosis was observed in PMNs isolated from both blood and milk of CM group of cows when compared to control and SCM group. The milk neutrophils of CM group of cows formed NETs as evidenced from the SEM images. Surface expression of CD44 revealed a significantly (p<0.05) lower expression in milk neutrophils of CM group of cows when compared to SCM and control group of cows. Conclusion: The study indicated a positive correlation between delayed neutrophil apoptosis, persistent staying of neutrophils at the site of infection along with formation of NETs as the strategies to fight against the pathogens in the udder during Staphylococcal mastitis. The study forms a strong base for future molecular research in terms of neutrophil recruitment and neutrophil removal from the site of infection.
Research in veterinary science
The accumulation of leucocytes in milk and in teat cistern tissues, and the presence of the cytokines interleukin-1 beta (IL-1 beta), tumour necrosis factor-alpha (TNF-alpha), interleukin-8 (IL-8), granulocyte-macrophage colony-stimulating factor (GM-CSF) and interferon-gamma (IFN-gamma) in milk was studied during inflammation in the lactating ovine udder induced by Staphylococcus aureus and Escherichia coli. Milk and/or teat tissue samples were taken before and four, eight and 24 hours after inoculation. Both S aureus and E coli induced a significant accumulation of leucocytes in milk, S aureus from eight hours with a peak after 24 hours, and E coli from four hours, with a peak after eight hours. After the inoculation of S aureus the numbers of subepithelial neutrophils in the teat cistern tissues were increased after four hours and had increased further by eight hours. After the inoculation of E coli, tissue neutrophil numbers peaked at four hours and were still high at eight hour...
Phagocyte Non-Protective and Protective Responses in Bovine Mammary Infections
2003
The presence of phagocyte-related cutoff points that distinguish protective from non-protective anti-28 bacterial responses was investigated in bovine mastitis. Five lactating cows were intra-mammarily 29 infused with Staphylococcus aureus and CD 11 b surface density (expressed as median fluorescence 30 intensity or MFI) was assessed (before and three times after challenge) in blood and milk phagocytes 31 by flow cytometry. CD 11 b MFI was compared to bacterial counts of milk cultures, the somatic cell 32 count (SCC), as well as the surface density of several lymphocyte differentiation antigens. In addition, 33 the ratio ofphagocytes (monocytes or macrophages [M0] plus polymorphonuclear cells [PMN]) to 34 lymphocytes, and the ratio ofPMN to M0, were determined. These measures differentiated non-35 mastitic from mastitic animals, identified very early (1 day post-infusion or pi), early (1 week pi) and 36 late (2 weeks pi) inflammations, and revealed CD 11 b MFI cutoff points above which no bacterial growth in milk cultures and SCC <500,000 cells/ml were observed ("immune thresholds"). For any given cell type, identical thresholds were shown in relation to both outcome indicators. Lower critical cutoff points (resulting in protective effects) were observed at 2 wpi than at 1 dpi. Immune thresholds distinguished individuals prone to mount efficient immune responses from those unable to do so, and also provided predictions on future outcomes based on pre-challenge measures. It is suggested that measurement of immune thresholds may improve prognosis of, and animal selection against, bovine mastitis. Control of bovine mastitis has historically been based on outcome measures, such as the Somatic Cell 46 Count (SCC) and bacterial counts (Sargeant et al., 2001). However, some measures used in the current 65 replication cycles occur within 2 hours, it may be expected that the resulting immune response will have to clear only 40 bacteria. In contrast, if naive T cells have been involved or if sub-optimal (or non-sustained) T-cell stimulation has occurred, it may take > 6 hours to generate an immune response which then would have to face a number of bacteria in the order of millions. The bacterial agent can also determine the outcome of the immune response. For instance, S. aureus invasions of the bovine mammary gland appear to result in poor (if not absent) IL-2 de novo 71 mRNA transcription (Riollet et al., 2000; Alluwaimi et al., 2003). Therefore, it may be assumed that S. aureus invasions induce sub-optimal immune responses. That is, a "slow" TCR triggering process may occur due to lack of IL-2 mediated signaling, which translates as an excessive number of 74 bacterial multiplications. In such case, the number of bacteria to be cleared may exceed the ability of the cow's immune system and, consequently, microbes may succeed in colonizing mammary tissues. intensively managed flocks and related changes in the yield and quality of ewe milk. Small