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Topic:Phagocytosis

Phagocytosis in horses refers to the process by which certain cells, known as phagocytes, engulf and digest foreign particles, bacteria, and cellular debris. This cellular mechanism is a part of the innate immune response, helping to protect horses from infections and maintain tissue homeostasis. Key phagocytic cells in horses include neutrophils and macrophages, which are responsible for identifying and eliminating pathogens. Research on phagocytosis in equines explores the efficiency, regulation, and impact of this process on overall health and disease resistance. This page includes peer-reviewed research studies and scholarly articles that investigate the mechanisms, cellular interactions, and implications of phagocytosis in equine immunology.
Dermal collagen degradation and phagocytosis. Occurrence in a horse with hyperextensible fragile skin.
Archives of dermatology    May 1, 1984   Volume 120, Issue 5 599-604 
Gunson DE, Halliwell RE, Minor RR.A 2-year-old female horse had large areas of hyperextensible, fragile skin that were interspersed with areas of normal skin. Affected skin tore easily and contained reduced amounts of dermal collagen. Collagen fibers were fragmented and disorganized, and in trichrome-stained sections, many fibers had abnormal red-stained centers. Electron microscopy showed that many collagen fibers had discrete foci of degradation in which the fibrils were fragmented, loosely packed, and widely separated by granular material. Collagen fibril fragments were present in secondary lysosomes in dermal fibroblasts, ...
Uterine defense mechanisms in the mare: Serum opsonins affecting phagocytosis of Streptococcus zooepidemicus by equine neutrophils.
Theriogenology    February 1, 1984   Volume 21, Issue 2 375-385 doi: 10.1016/0093-691x(84)90422-9
Asbury AC, Gorman NT, Foster GW.The addition of serum to uterine secretions was shown to opsonize Streptococcus zooepidemicus and significantly enhance bacterial phagocytosis by equine neutrophils. Treatment of serum by heat inactivation at 56 degrees C, EDTA treatment, and C3 consumption reduced phagocytosis and therefore demonstrated that the process was complement-dependent. The amount of C3 present in uterine secretions was measured in a series of 14 mares infected with Streptococcus zooepidemicus . Ten of the 14 mares had detectable amounts of C3; however, the C3 had been cleaved and rendered nonfunctional. The importan...
Myelopathy and vitamin E deficiency in six Mongolian wild horses.
Journal of the American Veterinary Medical Association    December 1, 1983   Volume 183, Issue 11 1266-1268 
Liu SK, Dolensek EP, Adams CR, Tappe JP.Degenerative myelopathy was diagnosed in six Mongolian wild horses. Three of the horses had a history of ataxia dating from birth to 3 months of age. The clinical signs were uncoordinated movement of the hindlimbs and an abnormally wide-based gait and stance. The other 3 horses had mild ataxia. There were no gross lesions in the brain, vertebrae, or spinal cord. Histologic examination revealed degeneration of the neural processes in the ventral and lateral funiculi of all 6 horses. Myelin sheaths were dilated and vacuolated, and there were swollen, fragmented, or lysed axons. Neuronal degenera...
Phagocytosis and intracellular killing of the contagious equine metritis organism by equine neutrophils in genital secretions.
American journal of veterinary research    October 1, 1983   Volume 44, Issue 10 1923-1927 
Bertram TA, Coignoul FL, Jensen AE.Equine neutrophils were combined with contagious equine metritis organism (CEMO) or Escherichia coli in vitro in the presence of seminal plasma, uterine flushings, or Hank's balanced salt solution (HBSS). Phagocytosis and intracellular killing were estimated by bacterial culture and light and electron microscopy. With lysed neutrophils, the numbers of colony-forming units of CEMO and E coli increased in seminal plasma and uterine flushings. Numbers of CEMO decreased in HBSS. The numbers of CEMO increased more in the presence of seminal plasma than the other media. When neutrophils were in the ...
Chemiluminescence response of equine alveolar macrophages during stimulation with latex beads, or IgG-opsonized sheep red blood cells.
Inflammation    June 1, 1983   Volume 7, Issue 2 169-182 doi: 10.1007/BF00917821
Dyer RM, Leid RW.Isolated equine alveolar macrophages were shown to generate a luminol-dependent light response when challenged with a phagocytic stimulus. The chemiluminescent response was not detected with luminol prepared at 1.0 x 10(-5) or 1.0 x 10(-4) molar concentrations, but was readily quantitated when used at a 1.0 x 10(-3) molar concentration. Challenge of the alveolar macrophages with latex particles or with equine IgG-coated sheep red blood cells elicited the luminol-dependent light response, whereas unchallenged equine alveolar macrophages or those challenged with unopsonized erythrocytes failed t...
Cytology, bacteriology and phagocytic capacity of tracheo-bronchial aspirates in healthy horses and horses with chronic obstructive pulmonary disease (COPD).
Zentralblatt fur Veterinarmedizin. Reihe A    February 1, 1983   Volume 30, Issue 2 114-120 doi: 10.1111/j.1439-0442.1983.tb00683.x
Nuytten J, Muylle E, Oyaert W, van den Hende C, Vlaminck K, de Keersmaecker F.No abstract available
Mononuclear phagocytes of peritoneal fluid.
Equine veterinary journal    October 1, 1982   Volume 14, Issue 4 325-328 doi: 10.1111/j.2042-3306.1982.tb02444.x
Brownlow MA.Cells in the peritoneal fluid from 179 horses were examined in Giemsa stained preparations using light microscopy. Mononuclear phagocytes were a common cell type observed in normal fluids. In the absence of stimulation they were morphologically similar to the peripheral blood monocyte and the unstimulated mesothelial cell. In acute inflammatory effusions their proportion decreased significantly but, as the condition resolved, monocytes began to migrate into the cavity gradually becoming more numerous, transforming into larger macrophages and assuming an increasing phagocytic role. They were of...
Phagocytosis and intracellular killing of the contagious equine metritis organism by equine neutrophils in serum.
Infection and immunity    September 1, 1982   Volume 37, Issue 3 1241-1247 doi: 10.1128/iai.37.3.1241-1247.1982
Bertram TA, Coignoul FL, Jensen AE.Equine neutrophils were combined with Haemophilus equigenitalis (contagious equine metritis organism; CEMO) or Escherichia coli in low- and high-antibody-titer serum to evaluate the neutrophils ability to phagocytize and kill these bacteria. More E. coli than CEMO were phagocytized at each time period. After 120 min in low-antibody-titer serum, 56.3% of the E. coli and 34.3% of the CEMO were phagocytized. A total of 45% of CEMO and 74.9% of E. coli were phagocytized by 120 min when neutrophils were in high-antibody-titer serum. More than 75% of the ingested E. coli and 90% of the ingested CEMO...
Effect of estrogen and progesterone on the phagocytic response of ovariectomized mares infected in utero with beta-hemolytic streptococci.
American journal of veterinary research    August 1, 1982   Volume 43, Issue 8 1367-1370 
Washburn SM, Klesius PH, Ganjam VK, Brown BG.No abstract available
Characterization of the chemiluminescence response of equine phagocytes.
American journal of veterinary research    July 1, 1982   Volume 43, Issue 7 1147-1151 
Washburn SM, Klesius PH, Ganjam VK.No abstract available
Mesothelial cells of peritoneal fluid.
Equine veterinary journal    January 1, 1982   Volume 14, Issue 1 86-88 doi: 10.1111/j.2042-3306.1982.tb02346.x
Brownlow MA, Hutchins DR, Johnston KG.Cells in the peritoneal fluid from 159 horses were examined in Giemsa stained preparations using light microscopy. Normal mesothelial cells showed an oval nucleus with finely reticular chromatin and pale blue cytoplasm. Activated mesothelial cells occurred in fluids derived from mesothelium under acute or subacute, non-septic stimulus and were remarkable for their pleomorphism and intense basophilia which may mimic neoplasia. Transformed mesothelial cells seen in chronic inflammatory fluids were sometimes phagocytic and showed conspicuous cytoplasmic vacuolation.
Factors affecting phagocytosis of bacteria by neutrophils in the mare’s uterus.
Journal of reproduction and fertility. Supplement    January 1, 1982   Volume 32 151-159 
Asbury AC, Schultz KT, Klesius PH, Foster GW, Washburn SM.Ten mares, 5 resistant and 5 susceptible to bacterial endometritis, were examined for differences pertaining to the efficiency of phagocytosis of bacteria by neutrophils in the uterus. An assay for chemiluminescence was used to evaluate various schemes of opsonization and relate them to phagocytic rate. 123I-labelled albumin was used to measure protein migration to the inoculated uterus. Neutrophil numbers moving to the uterine lumen were determined. Before inoculation resistant mares were found to have substances in their uterine secretions that opsonized bacteria, resulting in effective phag...
Studies on the composition and antibacterial activity of uterine fluid from mares.
Journal of reproduction and fertility. Supplement    January 1, 1982   Volume 32 143-149 
Blue MG, Brady AA, Davidson JN, Kenney RM.Forty uterine fluid samples were obtained during oestrus and dioestrus of successive cycles from 4 mares classified as resistant to bacterial infection of the uterus. The flushings were assayed for peroxidase activity and ability to influence phagocytosis by polymorphonuclear neutrophils. Uterine fluid volumes and protein concentrations and serum oestrogen values were similar during oestrus and dioestrus. Serum progesterone concentrations were depressed during oestrus. Equine neutrophils adherent to glass slides were exposed to a genital strain of Streptococcus zooepidemicus suspended in salin...
Effect of ovarian hormones on the phagocytic response of ovariectomized mares.
Journal of reproduction and fertility. Supplement    January 1, 1982   Volume 32 169-174 
Ganjam VK, McLeod C, Klesius PH, Washburn SM, Kwapien R, Brown B, Fazeli MH.The reaction between ovarian hormones and experimental uterine infection (Streptococcus zooepidemicus) was investigated in 3 groups, each containing 6 ovariectomized mares. Group 1 served as controls ('anoestrus'), Group 2 mares were injected with oestrogen ('oestrus') and Group 3 with progesterone ('dioestrus') over a period of 5 weeks. All mares received an intrauterine inoculation of the bacteria 1 week after the start of hormonal treatment, and the results of the challenge were examined by endometrial biopsy and swabs once weekly. At the end of Week 1 no bacteria were recovered from the ma...
Effect of total calorific deprivation on host defence in the horse.
Research in veterinary science    November 1, 1981   Volume 31, Issue 3 369-372 
Naylor JM, Kenyon SJ.Horses were deprived of food but not water for a period of five days. There was a progressive decrease in circulating lymphocyte count and compromised host deference. In vitro phagocytosis of yeast fell from a mean of 97 per cent in fed horses to 78 per cent in horses deprived of food for five days. The Arthus response to intradermal challenge with allergens fell to 57 per cent of fed values. These changes indicated that food deprivation increases the susceptibility to bacterial infections; persistent anorexia in chronic bacterial infections may limit the horse's ability to cast off infection....
Scanning electron microscopy of ciliary zones of the ciliate protozoa in the large intestine of the horse.
The Journal of parasitology    June 1, 1979   Volume 65, Issue 3 434-440 
Imai S, Ozeki K, Fujita J.The surface structure of the ciliary zone in 13 species of ciliates found in the large intestine of the horse was observed by scanning electron microscopy. In Holophryoides ovalis many fine depressions considered to be a result of phagocytosis or pinocytosis in the naked cytostome were noticed. In Blepharocorys spp. a distinct section was present between the portion with cilia and that without cilia. It was not present, however, in some species of the family Buetschliidae, such as Bundleia postciliata and Didesmis spp. The species of Entodiniomorphida had a lip around the ciliary zone with cil...
A rapid and simple method for the isolation of pure eosinophilic leukocytes from horse blood.
Experientia    December 15, 1978   Volume 34, Issue 12 1654-1656 doi: 10.1007/BF02034734
Jörg A, Portmann P, Fellay G, Dreyer JL, Meyer J.An improved and short method is described for the isolation of intact eosinophilic leukocytes from horse blood with high yield (1--1.5 g/20 l). Viability and purity of the preparations were verified by light and electron microscopy and by the trypan blue exclusion test. Isolated eosinophils were 98--100% pure, intact and viable, and they could be shown to phagocytise immune-complexes.
Granulomatous enteritis in nine horses.
Journal of the American Veterinary Medical Association    September 15, 1976   Volume 169, Issue 6 603-609 
Merritt AM, Cimprich RE, Beech J.Granulomatous enteritis was diagnosed in 9 horses between 1 and 11 years of age. The complaint in all cases was persistent weight loss. Four of the horses had chronic diarrhea. Two consistent diagnostic features were hypoalbuminemia and decreased phagocytic activity of mesothelial cells in the peritoneal fluid. In 2 cases the diagnosis was confirmed by biopsy of the rectal mucosa. Remaining cases were definitively diagnosed by exploratory laparotomy and biopsy or at necropsy.
[Effect of ultraviolet ray-irradiated autogenous blood on hematological indices in horses].
Veterinarno-meditsinski nauki    January 1, 1976   Volume 13, Issue 10 11-19 
Bodurov N, Filipov Zh.Comparative clinical and experimental investigations were carried out on 18 clinically normal horses. It was found that the single transfusion of in vitro UV-treated autogenous blood, following a previously described method, was tolerated well by horses and did not lead to any deviations from the normal indices. Under the effect of the treated blood there was an increase in the hemoglobin content, rise in the erythrocyte and leukocyte count with slightly expressed hyperleukocytosis and weak neutrophilia (simple regeneration of the blood). The sedimentation of erythrocytes also showed higher ra...
Ultrastructure of the synovial membrane.
Annals of clinical and laboratory science    November 1, 1975   Volume 5, Issue 6 489-498 
Schumacher HR.The normal synovial membrane as seen by electron microscopy is bordered by one to three layers of lining cells that include some with phagocytic function, others rich in endoplasmic reticulum for protein synthesis and additional cells with mixed properties. Lining cells with prominent Golgi apparatus probably produce the synovial hyaluronic acid. The synovial matrix contains collagen and mucopolysaccharide. It offers little barrier to diffusion of most materials. Superficial capillaries and venules are fenestrated and presumably allow rapid exchange of fluid and electrolytes. Deeper venules ha...
Origin and histogenesis of equine endometrial cups.
Journal of reproduction and fertility. Supplement    October 1, 1975   Issue 23 391-395 
Moor RM, Allen WR, Hamilton DW.Biochemical and morphological studies were carried out to determine the origin and histogenesis of endometrial cups in mares. A wide range of fetal and maternal tissues were cultured in vitro and their ability to secrete gonadotrophin (PMSG) was monitored. High levels of PMSG were produced in culture only by cells from the restricted area of the equine trophoblast known as the chorionic girdle which is an annular band of highly specialized cells at the junction of the allantois and the regressing yolk sac. The morphological appearance of girdle cells after cultivation in vitro and after alloge...
Opsonizing properties of horse sera. 3. The role of the specific and nonspecific factors stimulating phagocytosis of Salmonella typhimurium in horse sera.
Archivum immunologiae et therapiae experimentalis    January 1, 1966   Volume 14, Issue 1 25-31 
Grzybek-Hryncewicz K, Ladosz J, Kubis K, Slopek S.No abstract available
Opsonizing properties of horse sera. II. Factors stimulating phagocytosis of Shigella sonnei (phase II) bacilli.
Archivum immunologiae et therapiae experimentalis    January 1, 1966   Volume 14, Issue 1 19-24 
Grzybek-Hryncewicz K, Ladosz J, Kubis K, Slopek S.No abstract available
[On the effect of pain stimuli on the phagocyte activity of the leukocytes in horses].
Biulleten' eksperimental'noi biologii i meditsiny    February 1, 1960   Volume 49 81-85 
RUSINOV AF.No abstract available
A Study of Pneumococci Isolated from Horses Undergoing Pneumococcus Immunization.
The Journal of experimental medicine    April 30, 1927   Volume 45, Issue 5 787-797 doi: 10.1084/jem.45.5.787
Wadsworth AB, Sickles GM.IT HAS BEEN SHOWN THAT THE PNEUMOCOCCUS MULTIPLYING IN THE TISSUES OF THE IMMUNIZED ANIMAL (HORSE) BECOMES ATTENUATED: loses, in varying degrees, its virulence, capacity of capsule formation, susceptibility to phagocytosis, and type specificity. The antigenic activity as an immunizing agent and the production of "soluble specific substance" are also altered. In some instances, the typical pneumococcus characteristics may be quickly restored by one or two passages through a susceptible animal (mouse). In others, virulence is not recovered and the organism remains atypical. Whether these changes...
The Occurrence of Degraded Pneumococci in Vivo.
The Journal of experimental medicine    April 30, 1927   Volume 45, Issue 5 807-814 doi: 10.1084/jem.45.5.807
Reimann HA.It is conceivable that a change from the virulent, non-phagocytable S form of Pneumococcus to the avirulent phagocytable R form may take place in pneumococcus disease, but the experiments here reported do not settle the question whether or not this is an important factor in determining the outcome in natural infection. It has been shown experimentally that the degradation from the S form to the R form actually does take place in cultures of Pneumococcus growing in agar subcutaneously embedded in guinea pigs, in agar enclosed in vials subcutaneously embedded in rabbits, and spontaneously in the...
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