Supramammary Lymph Nodes Research Articles

Effects on adhesion molecule expression and lymphocytes in the bovine mammary gland following intra-mammary immunisation

Changes to adhesion molecule expression and lymphocyte populations were evaluated in alveolar mammary tissue collected from cows following an immunisation protocol that involved intra-mammary inoculation to induce an IgA response in mammary secretions. The right quarters of the udder were immunised; the left side acted as a control. Antibody titres in secretions showed that at least two animals responded with antigen-specific IgA. Numbers of T-lymphocytes were 4-fold higher in immunised glands compared with controls ( P < 0.05). IgA-, IgM- and IgG-positive cell numbers were significantly higher ( P < 0.01) in immunised glands compared with controls in three of the four cows. No mucosal addressin molecule-1 (MAdCAM-1), vascular cell-adhesion molecule-1 (VCAM-1) or peripheral node addressin (PNAd) protein expression was detected on smaller venules that stained positively for von Willebrand factor in alveolar mammary tissues, from either immunised or control glands. Both VCAM-1 and PNAd were detected on smaller venules in supramammary lymph nodes, however, there was no significant difference between immunised and control glands. Quantification of MAdCAM-1 mRNA showed very low expression in both immunised and control alveolar tissue compared with Peyer's patch positive-control tissue. These findings suggest that the bovine mammary gland is capable of a mucosal antibody response; however, MAdCAM-1 is not involved with lymphocyte homing to the mammary gland in this species.

Pathological, Immunohistochemical, and Bacteriological Findings in the Mammary Glands and Supramammary Lymph Nodes of Cows with a History of Abortion due to Brucella abortus

The present study examined the mammary glands and supramammary lymph nodes of cows with a history of abortion due to Brucella abortus, and presents the histopathological, immunohistochemical, and bacteriological results. The study included 11 Brucella-seropositive cows that aborted during their first gestation. Histopathologically, the mammary glands showed lymphoplasmacytic and histiocytic interstitial mastitis. The lymph nodes had lymphofollicular hyperplasia and medullary plasmacytosis. Immunohistochemistry results showed brucellar antigens, predominantly in the cytoplasm of macrophages, and neutrophils in the intralobular interstitium and periductal stroma in the udders of 3 cows. Desquamated alveolar epithelium also indicated intense immunopositivity. In the lymph nodes, macrophages containing the antigen were frequently observed in the medullary region. B. abortus biotype 3 was isolated from the udders and supramammary lymph nodes of 4 cows. Although the most specific procedure for diagnosing the disease is isolation of the causative organism, for suspected cases in which the bacteriologic culture is negative or the material is fixed in formalin, immunohistochemistry may be used as a diagnostic tool for the detection of Brucella organisms.

Induction of HIV-1 MPR649–684-specific IgA and IgG antibodies in caprine colostrum using a peptide-based vaccine

Induction of antigen-specific antibodies against HIV-1 in colostrum and milk may help prevent breast milk transmission of the virus. A peptide vaccine against the HIV-1 gp41 membrane proximal region (MPR649–684) was evaluated as proof-of-principle in a caprine model. Pregnant Alpine/Saanen goats were immunized with MPR649–684 peptide conjugated to KLH using alum adjuvant. Immunizations were intramuscular, intranasal, and in the supramammary lymph node region. Samples collected after parturition demonstrated the presence of MPR649–684-specific antibodies in colostrum and serum. These results support the concept that a peptide vaccine can effectively induce MPR649–684-specific sIgA and IgG in the colostrum of a lactating species.

Transfer of immunoglobulins through the mammary endothelium and epithelium and in the local lymph node of cows during the initial response after intramammary challenge with E. coli endotoxin.

BackgroundThe first hours after antigen stimulation, interactions occur influencing the outcome of the immunological reaction. Immunoglobulins originate in blood and/or are locally synthesized. The transfer of Ig isotypes (Igs) in the udder has been studied previously but without the possibility to distinguish between the endothelium and the epithelium. The purpose of this study was to map the Ig transfer through each barrier, separately, and Ig transfer in the local lymph nodes of the bovine udder during the initial innate immune response.MethodsThe content of IgG1, IgG2, IgM, IgA and albumin (BSA) was examined in peripheral/afferent mammary lymph and lymph leaving the supramammary lymph nodes, and in blood and milk before (0 h) and during 4 hours after intramammary challenge with Esherichia coli endotoxin in 5 cows.ResultsIgs increased most rapidly in afferent lymph resulting in higher concentrations than in efferent lymph at postinfusion hour (PIH) 2, contrary to before challenge. Ig concentrations in milk were lower than in lymph; except for IgA at 0 h; and they increased more slowly. Afferent lymph:serum and efferent lymph:serum concentration ratios (CR) of Igs were similar to those of BSA but slightly lower. Milk:afferent lymph (M:A) CRs of each Ig, except for IgG2, showed strikingly different pattern than those of BSA. The M:A CR of IgG1, IgM and IgA were higher than that of BSA before challenge and the CR of IgA and IgG1 remained higher also thereafter. At PIH 2 there was a drop in Ig CRs, except for IgG2, in contrast to the BSA CR which gradually increased. The M:A CR of IgM and Ig A decreased from 0 h to PIH 4, in spite of increasing permeability.ConclusionThe transfer of Igs through the endothelium appeared to be merely a result of diffusion although their large molecular size may hamper the diffusion. The transfer through the epithelium and the Ig concentrations in milk seemed more influenced by selective mechanisms and local sources, respectively. Our observations indicate a selective mechanism in the transfer of IgG1 through the epithelium also in lactating glands, not previously shown; a local synthesis of IgA and possibly of IgM, released primarily into milk, not into tissue fluid; that IgG2 transfer through both barriers is a result of passive diffusion only and that the content of efferent lymph is strongly influenced by IgG1, IgM and IgA in the mammary tissue, brought to the lymph node by afferent lymph.

Evaluation of interleukin-2 treatment for prevention of intramammary infections in cows after calving

A low-dose treatment based on interleukin-2 (IL-2) was investigated for preventing mastitis in dairy cows. The treatment consisted of a single dose of IL-2 injected into the skin region drained by the supramammary lymph node 3-5 days after calving. The study included 45 cows (23 treated and 22 controls) from three commercial dairy herds. The results showed that the treatment had no side effects. The treatment with IL-2 induced the significant increase of several milk markers related to leukocyte and epithelial cell functions, i.e. SCC (somatic cell counts), serum amyloid A (SAA), lactoferrin and NAGase. The increased concentration of milk markers suggested also an activity of IL-2 on epithelial cells, resulting in a higher resistance to invading pathogens. Indeed, the increased efficiency of cells in the udder is supported by the higher frequency of healthy quarters observed in the treated group until day 17-19 after calving, in comparison with the control one.

Influence of supramammary lymph node extract on in vitro cell proliferation

Experiments were conducted to evaluate whether or not bovine supramammary lymph node extract (LNE) could support cell proliferation when it was substituted for bovine growth serum (BGS) in cell culture media. Two different preparations of LNE were tested. The first yielded protein concentration of 3 mg/mL and the second contained 27 mg/mL protein. Three cell lines (MDA-MB-435, MAC-T and 1C6) were used in serum starvation assays to evaluate LNE. Cell proliferation assays were used to determine growth stimulation in the presence of LNE, and short-term or rapid adaptation cultures were evaluated for LNE effects on cell survival. Heat-inactivated preparation 1 supported cell proliferation as well as or better (12-39%) than BGS following 2 days of serum starvation in culture. The second lymph node preparation provided a stimulatory effect (263-702% greater than BGS across all cell lines) following serum starvation at 2.7 and 5.4 mg/mL protein supplementation. A gradual adaptation process with lymph node supplementation into media maintained cell population growth on a short-term basis. However, once cells were trypsinized or scraped and re-seeded into 2.7 mg/mL LNE protein containing media, cells were unable to re-adhere, leaving them detached, and eventually appearing to be dead. Substitution of BGS with LNE protein dramatically stimulated cells to proliferate, but did not allow for rapid cell population growth adaptation in vitro.

Brucellosis in Camels (Camelus dromedarius) in Darfur, Western Sudan

In a field outbreak of brucellosis in 21 camels mixed with cattle, sheep and goats, five camels, three of which showed clinical signs, were serologically positive. In a subsequent abattoir survey of apparently healthy camels, six animals were seropositive, albeit with titres that tended to be lower than those found in the field outbreak. Of the six seropositive slaughtered camels, five were shown to have lymph nodes (prescapular and supramammary) infected with brucellae (Brucella melitensis biovar 3, two camels; Brucella abortus biovar 6, three camels). Infection of camels with B. abortus biovar 6 had not previously been reported. Infection of the supramammary lymph nodes presents a potential hazard to those who consume raw camels' milk, a common practice in nomadic camel owners.

Total and Differential Leucocyte Counts and Lymphocyte Subpopulations in Lymph, Afferent and Efferent to the Supramammary Lymph Node, During Endotoxin‐Induced Bovine Mastitis

Leucocyte trafficking in afferent and efferent mammary lymph and the supramammary lymph node in cows was examined during 4 h after intramammary infusion of endotoxin from Escherichia coli. Total and differential leucocyte counts were measured in milk, blood and lymph. The proportions of CD4(+), CD8(+), major histocompatibility complex (MHC) class II(+) and IgM(+) lymphocytes were examined in the lymph and lymph node. At post-infusion hour (PIH) 4, the flow rates of both lymph fluids had increased approximately eightfold. Total leucocyte concentration increased in afferent lymph, but decreased in efferent lymph. Neutrophils increased in afferent lymph at PIH 2 and in efferent lymph and milk at PIH 4. The predominant cell type in afferent lymph shifted from lymphocyte to neutrophil while lymphocyte was still at PIH 4 the predominant type in efferent lymph. Among the lymphocytes, B cells were predominant in afferent lymph and lymph node at PIH 4 while T cells, mainly CD4(+) cells, were predominant in efferent lymph both at PIH 0 and PIH 4. The CD4 : CD8 ratio was higher in efferent lymph and the challenged lymph node than in afferent lymph and the control node, respectively. There was a significant difference in proportions of each lymphocyte subpopulation except for IgM(+) cells, between afferent and efferent lymph after infusion. According to the results, there was already during the first hours of the immune response, a non-random trafficking of neutrophils and lymphocyte subpopulations resulting in a changed distribution of cells in afferent and efferent lymph and a difference in lymphocyte reactivity between the two lymph fluids.

Adhesion molecule expression in the bovine mammary gland

The bovine mammary gland requires lymphocytes for immune protection of the gland from foreign pathogens and, in addition, to transfer immune protection to the neonate via colostrum and milk. The process of homing primed lymphocytes to tissues is mediated by the interaction of cell-adhesion molecules displayed on the surface of lymphocytes and counter receptors displayed on the vascular endothelium. This study was conducted to identify the cell-adhesion molecules involved in homing lymphocytes to the bovine mammary gland at four different physiological stages; pregnant, colostral, lactation and involution. The expression and distribution of adhesion molecules in alveolar tissues and supramammary lymph nodes from the mammary glands of healthy cows was determined in situ by immunohistochemical analysis and compared with bovine Peyer's patch, used as a typical mucosal-associated lymphoid tissue and positive control. The mucosal addressin molecule, MAdCAM-1, was not detected in bovine mammary tissues at any of the four different physiological stages. Absence of MAdCAM-1 expression was verified by quantitative real-time RT-PCR analysis. Transcription levels of MAdCAM-1 mRNA were found to be more then 5 × 10 3-fold lower in mammary alveolar tissues compared with bovine Peyer's patch tissues. In contrast to MAdCAM-1, phase-dependent protein expression of VCAM-1 was detected in both mammary alveolar tissues and the supramammary lymph nodes, with the highest expression observed in colostral phase cows. The protein expression in mammary alveolar tissues was limited to larger venules, although in colostral phase cows, VCAM-1 was also detected around the alveoli perimeter. In the supramammary lymph node, VCAM-1 protein was observed on both small and large venules. PNAd was detected in supramammary lymph nodes at all physiological stages of the mammary gland; however, it was not found in mammary alveolar tissues. Lymphocytes expressing β7 were not detected in mammary tissues and lymphocytes expressing CD62L were only observed in the supramammary lymph nodes. Overall the data suggest that MAdCAM-1 and VCAM-1 are not involved in homing lymphocytes to the bovine mammary gland; whereas, VCAM-1 and PNAd may have this role in the supramammary lymph node.

Lymphocytes from one side of the bovine mammary gland migrate to the contra lateral gland and lymph node tissue

The four quarters of bovine mammary glands are completely separated and two quarters on each side (right or left) are connected to ipsi lateral supra mammary lymph nodes. It is not clear whether cells infused into the cistern of the mammary gland are capable of migrating to lymph nodes or the general circulation. To examine cell migration, a prescapular lymph node was removed from each of two lactating and three non-lactating dairy cows, and isolated lymphocytes were stained with Hoechst 33342. Autologous stained cells were infused into the mammary gland and then activated by intramammary infusion of zymosan-stimulated serum (source of C5a). After 17 h, Escherichia coli J5 bacterin was infused into the contra lateral mammary gland to mimic infection. After 43 h cows were euthanized and tissue samples (mammary quarters, right and left supra mammary, mesenteric, ileocecal and prescapular lymph nodes, liver and spleen) were collected for microscopic examination as well as flow cytometric analysis. Hoechst stained cells were detected not only in infused quarters, but also in contra lateral quarters as well as in both supra mammary lymph nodes. This indicates that cells infused into the mammary gland migrate to contra lateral tissues and supra mammary lymph nodes.

Pulsed-field gel electrophoresis patterns of Mycoplasma isolates from various body sites in dairy cattle with Mycoplasma mastitis

To determine whether Mycoplasma strains typically associated with mastitis in dairy cattle can be isolated from body sites other than the mammary gland. Prospective clinical trial. 7 Holstein cows in various stages of lactation with intramammary Mycoplasma infection. Milk samples, antemortem swab specimens from various body sites, and postmortem swab and tissue specimens were submitted for Mycoplasma culture. Pulsed-field gel electrophoresis (PFGE) was performed on chromosomal digests of all Mycoplasma isolates. Isolates with the same number and size of chromosomal digest bands were considered to be of the same type. For each cow, all isolates obtained from milk, mammary gland parenchyma, and supramammary lymph nodes had the same PFGE pattern. All cows had at least 1 isolate from nonmammary system tissues that had the same PFGE pattern as isolates from the mammary system. Overall, 44 of the 70 (63%) Mycoplasma isolates obtained from body sites other than mammary system sites had the same PFGE pattern as did mammary system isolates. Results confirmed our hypothesis that Mycoplasma strains isolated from the milk of dairy cattle with Mycoplasma mastitis frequently have PFGE patterns identical to those for strains isolated from other body sites, suggesting that there is at least a potential for internal transmission of Mycoplasma organisms.

Experimental Corynebacterium pseudotuberculosis mastitis in dairy cows

The inoculation of 2000 colony-forming units of Corynebacterium pseudotuberculosis into one teat canal of each of three cows resulted in severe, chronic, pyogranulomatous mastitis. Within three days the cows had...

Optimization of DNA vaccination immune responses in dairy cows: effect of injection site and the targeting efficacy of antigen-bCTLA-4 complex

The objectives of this study were to evaluate the effects of immunization site and antigen presenting cell targeting on cattle immune responses to DNA immunization. Cows were vaccinated with the plasmid expression vector pCI alone, pCI encoding the bacterial antigen β-galactosidase (pCI-β-gal) or pCI encoding bCTLA 4 fused to β-gal (pCI-bCTLA-hIgG-β-gal). The plasmids were delivered by intramuscular, intradermal, intramammary gland, or intra supramammary lymph node needle-injection. Both vaccines induced significant humoral and cellular immune responses. pCI-β-gal elicited a higher IgG response than immunization with pCI-bCTLA-hIgG-β-gal. Cows injected intramuscularly and intramammary had higher IgG and IgG-1 humoral responses than cows immunized intradermaly or in the lymph nodes. The injection site did not significantly affect the magnitude of the IgG2 and IgM antibody responses, although a trend similar to the IgG results was observed. The lymphocyte proliferation index was higher with pCI-β-gal but was not affected by the injection site. These results suggest that in bovine, the injection site can affect immune responses but they do not provide evidence that bCTLA-4-hIgG-antigen targeting is effective in cattle.

Efficacy of calfhood vaccination with Brucella abortus strain RB51 in protecting bison against brucellosis

In the studies reported here, protection induced by calfhood vaccination of bison with 1.2–6.1×10 10 CFU of Brucella abortus strain RB51 (SRB51) against a virulent strain of B. abortus was evaluated. Non-vaccinated and SRB51-vaccinated bison were intraconjunctivally challenged during midgestation with 3×10 7 CFU of virulent B. abortus strain 2308 (S2308). Maternal and fetal tissues were obtained within 24 hour after abortion or parturition. Incidence of abortion was greater ( P<0.05) in non-vaccinated as compared to SRB51-vaccinated bison (62% and 15%, respectively), with abortions occurring between 5 and 8 weeks after experimental challenge. Calves from bison vaccinated with SRB51 had a reduced ( P<0.05) prevalence of fetal infection with S2308 as compared to calves from non-vaccinated bison (19% and 62%, respectively). Although the ability to recover the 2308 challenge strain from maternal tissues did not differ ( P>0.05) between nonvaccinates and vaccinates (100% and 78%, respectively), calfhood vaccination with SRB51 reduced ( P<0.05) recovery of S2308 from uterine or mammary gland tissues. In bison which did not abort, S2308 was routinely recovered in low numbers from maternal lymphatic tissues; particularly the parotid, bronchial, supramammary, and mandibular lymph nodes. The RB51 vaccine strain was not recovered at any time from maternal or fetal samples obtained at necropsy. Histological lesions associated with Brucella-induced abortions were suppurative placentitis, fetal broncho-interstitial pneumonia, and fetal histiocytic splenitis. The results of our studies suggest that calfhood vaccination of bison with SRB51 is efficacious in protecting against intramammary, intrauterine, and fetal infection following exposure to a virulent strain of B. abortus during pregnancy. As brucellosis is transmitted horizontally through fluids associated with the birth or abortion of an infected fetus, or vertically to the calf through the ingestion of milk containing B. abortus, our data suggest that calfhood vaccination with SRB51 will be beneficial in preventing transmission of brucellosis in bison.

Cytokines in mammary lymph and milk during endotoxin-induced bovine mastitis

Cytokine kinetics were examined in milk and in afferent and efferent lymph of the supramammary lymph node after intramammary infusion of endotoxin from Escherichia coli. Cows were sampled 0, 2 and 4 h after infusion (p.i.). Neutrophils appeared in afferent lymph 2 h p.i., and in efferent lymph and milk 4 h p.i. The milk contained high concentrations of interleukin-8 (IL-8) at 2 and 4 h p.i. IL-8 was also found in lymph, but at lower concentrations. The tumor necrosis factor-α (TNF-α) concentration tended to increase in afferent lymph at 2 h p.i., and increased in milk at 4 h p.i. The level of IL-1β increased at 4 h p.i. in milk, but was not detected in lymph. Interferon-γ was not detected in any sample, at any time. The results indicate a primary role for IL-8 in the recruitment of neutrophils into the gland, and suggest that IL-1β and TNF-α are not necessary for IL-8 production and release in response to endotoxin.

Immunization with Staphylococcus aureus Lysate Incorporated into Microspheres

Antibiotics are of limited value against Staphylococcus aureus due to development of resistant strains, scar tissue formation, and blockage of ducts due to inflammation. Though macrophages are the predominant cell type in the mammary gland, they are primarily scavenger cells and are not effective against bacteria entering the gland. Neutrophil phagocytosis is the bovine's primary defense against S. aureus mastitis. Attempts to develop vaccines that enhance neutrophil phagocytosis by stimulating production of opsonizing antibodies to S. aureus have met with limited success because of the low immunogenicity of the exopolysaccharide capsule surrounding S. aureus. Staphylococcus aureus can also adhere to and penetrate epithelial tissue. This study was conducted to determine whether lysates of S. aureus encapsulated in biodegradable microspheres would increase the production of opsonizing antibodies to capsule and block adherence. Four groups of four cows each were injected with 1ml of the respective treatment in the area of the supramammary lymph node and 1ml in the hip muscle. The treatments were: lysate in NaCl, lysate in Freund's incomplete adjuvant (FICA), lysate in microspheres in NaCl, and lysate in microspheres in FICA. Antigen in microspheres produced a similar antibody response to antigen emulsified in FICA, but to a lesser magnitude. Antigen in microspheres produced antibodies that were more opsonic for neutrophils at 20 and 52 wk postimmunization and inhibited S. aureus adherence to mammary epithelium. Ability to control antigen release and presentation, and the benefit of a single injection for long-term immunity using microspheres warrants additional studies.

Dynamics of Staphylococcus aureus infections during vaccination with an autogenous bacterin in dairy cattle.

The effect of an autogenous vaccine against Staphylococcus aureus on S. aureus prevalence and mastitis, as well as on somatic cell count (SCC), was studied in a dairy herd with a high prevalence of S. aureus. The vaccination group (n = 35; 22 cows and 13 heifers) and the control group (n = 36; 23 cows and 13 heifers) received the vaccine or a placebo, respectively, according to the following protocol: all animals: basic immunization (twice, 3 weeks apart); cows: booster dose at the time of drying off, 5 and 2 weeks before calculated calving date; heifers: booster dose 2 and 5 weeks before calculated calving date. The vaccine or the placebo was administered subcutaneously in the area of the supramammary lymph nodes. Quarter milk samples were collected monthly and subjected to SCC and bacteriological evaluation. At this time, the animals were also checked for signs of clinical mastitis. Non-clinical S. aureus mastitis diagnoses were based on udder quarter SCC and a positive S. aureus culture. In order to compare the SCC in individual whole milk samples, records from the monthly milk quality testing were evaluated. Cow and udder quarter prevalence of S. aureus intramammary infections calculated for the experimental animals and quarters, respectively, did not differ between groups. However, during the lactation period following the boostcr dose, the prevalence of S. aureus increased in both groups (P < 0.05). The cumulative incidence of various mastitis diagnoses (clinical, subclinical, latent infection) due to S. aureus on an animal basis did not differ between groups. On an udder quarter basis, the cumulative incidence of subclinical mastitis was higher in vaccinated animals than in control animals (33.8 versus 26.0%; P < 0.05). This was mainly due to a higher cumulative incidence of subclinical mastitis in vaccinated than control heifers. The SCC in composite milk samples did not differ between groups, but increased as lactation progressed. The herd prevalence of S. aureus differed considerably throughout the study period, but declined consistently to below 10% at the end of the study period. Recent herd checks revealed a prevalence of S aureus infections of < 5%. It is concluded that the autogenous bacterin tested in this study did not have the desired effect on the prevalence of S. aureus infections and mastitis or SCC. The decline in S. aureus prevalence was very probably due to other factors than specific immunization against S. aureus.

Ultrasonographic appearance of the superficial supramammary lymph nodes in lactating dairy cattle

The superficial supramammary lymph nodes of 54 lactating dairy cows were examined ultrasonographically with a 7-5 MHz linear transducer; each node was measured in two planes within 24 hours of...

Pathology of brucellosis in bison from Yellowstone National Park.

Between February 1995 and June 1999, specimens from seven aborted bison (Bison bison) fetuses or stillborn calves and their placentas, two additional placentas, three dead neonates, one 2-wk-old calf, and 35 juvenile and adult female bison from Yellowstone National Park (USA) were submitted for bacteriologic and histopathologic examination. One adult animal with a retained placenta had recently aborted. Serum samples from the 35 juvenile and adult bison were tested for Brucella spp. antibodies. Twenty-six bison, including the cow with the retained placenta, were seropositive, one was suspect, and eight were seronegative. Brucella abortus biovar 1 was isolated from three aborted fetuses and associated placentas, an additional placenta, the 2-wk-old calf, and 11 of the seropositive female bison including the animal that had recently aborted. Brucella abortus biovar 2 was isolated from one additional seropositive adult female bison. Brucella abortus was recovered from numerous tissue sites from the aborted fetuses, placentas and 2-wk-old calf. In the juvenile and adult bison, the organism was more frequently isolated from supramammary (83%), retropharyngeal (67%), and iliac (58%) lymph nodes than from other tissues cultured. Cultures from the seronegative and suspect bison were negative for B. abortus. Lesions in the B. abortus-infected, aborted placentas and fetuses consisted of necropurulent placentitis and mild bronchointerstitial pneumonia. The infected 2-wk-old calf had bronchointerstitial pneumonia, focal splenic infarction, and purulent nephritis. The recently-aborting bison cow had purulent endometritis and necropurulent placentitis. Immunohistochemical staining of tissues from the culture-positive aborted fetuses, placentas, 2-wk-old calf, and recently-aborting cow disclosed large numbers of B. abortus in placental trophoblasts and exudate, and fetal and calf lung. A similar study with the same tissue collection and culture protocol was done using six seropositive cattle from a B. abortus-infected herd in July and August, 1997. Results of the bison and cattle studies were similar.

乳用牛の腰部にみられた悪性線維性組織球腫の1例

A tumor mass 8 cm in diameter, was noticed on the left lumbar area of a 5-year-old dairy cow and enlarged to 16 cm in diameter 5 months later. The cow calved one month later, but was euthanatized at 2 months postpartum, because of deteriorating condition with decreased milk production. Grossly, the epidermis overlying the tumor was hyperkeratotic and partially ulcerated. The tumor affected the dermis, subcutis and muscles with necrotic or hemorrhagic foci at the center, extending to the peritoneum. The left subiliac, supramammary, medial iliac and lumbar aortic lymph nodes were enlarged. Microscopy revealed that the tumor tissue consisted of dense proliferation of fibroblastoid and histiocytoid cells, partly with foamy cells or multinucleated giant cells. Erythrophagia by histiocytoid cells was observed in hemorrhagic foci. Ultrastructurally, histiocytoid cells had abundant cytoplasmic organelles, as well as desmosome-like structures between adjoining cells.