Long-term antibody production and viremia in American mink (Neovison vison) challenged with Aleutian mink disease virus.

BACKGROUND: Selecting American mink (Neovison vison) for tolerance to Aleutian mink disease virus (AMDV) has gained popularity in recent years, but data on the outcomes of this activity are scant. The objectives of this study were to determine the long-term changes in viremia, seroconversion and survival in infected mink. Mink were inoculated intranasally with a local isolate of Aleutian mink disease virus (AMDV) over 4 years (n = 1742). The animals had been selected for tolerance to AMDV for more than 20 years (TG100) or were from herds free of AMDV (TG0). The progenies of TG100 and TG0, and their crosses with 25, 50 and 75% tolerance ancestry were also used. Blood samples were collected from each mink up to 14 times until 1211 days post-inoculation (dpi) and were tested for viremia by PCR and for anti-AMDV antibodies by counter-immunoelectrophoresis (CIEP). Viremia and CIEP status were not considered when selecting replacements. Low-performing animals were pelted and the presence of antibodies in their blood and antibody titer were measured by CIEP, and viremia and viral DNA in seven organs (n = 936) were tested by PCR. RESULTS: The peak incidences of viremia (66.7%) and seropositivity (93.5%) were at 35 dpi. The incidence of viremia decreased over time while the incidence of seroconversion increased. The least-squares means of the incidence of PCR positive of lymph node (0.743) and spleen (0.656) were significantly greater than those of bone marrow, liver, kidneys, lungs and small intestine (0.194 to 0.342). Differences in tolerant ancestry were significant for every trait measured. Incidences of viremia over time, terminal viremia, seropositivity over time, AMDV DNA in organs and antibody titer were highest in the susceptible groups (TG0 or TG25) and lowest in the tolerant groups (TG100 or TG75). CONCLUSION: Previous history of selection for tolerance resulted in mink with reduced viral replication and antibody titer. Viremia had a negative effect and antibody production had a positive effect on survival and productivity.

AMDV Vaccine: Challenges and Perspectives.

Aleutian mink disease virus (AMDV) is known to cause the most significant disease in the mink industry. It is globally widespread and manifested as a deadly plasmacytosis and hyperglobulinemia. So far, measures to control the viral spread have been limited to manual serological testing for AMDV-positive mink. Further, due to the persistent nature of this virus, attempts to eradicate Aleutian disease (AD) have largely failed. Therefore, effective strategies to control the viral spread are of crucial importance for wildlife protection. One potentially key tool in the fight against this disease is by the immunization of mink against AMDV. Throughout many years, several researchers have tried to develop AMDV vaccines and demonstrated varying degrees of protection in mink by those vaccines. Despite these attempts, there are currently no vaccines available against AMDV, allowing the continuation of the spread of Aleutian disease. Herein, we summarize previous AMDV immunization attempts in mink as well as other preventative measures with the purpose to shed light on future studies designing such a potentially crucial preventative tool against Aleutian disease.

Detection of selection signatures for response to Aleutian mink disease virus infection in American mink.

Aleutian disease (AD) is the most significant health issue for farmed American mink. The objective of this study was to identify the genomic regions subjected to selection for response to infection with Aleutian mink disease virus (AMDV) in American mink using genotyping by sequencing (GBS) data. A total of 225 black mink were inoculated with AMDV and genotyped using a GBS assay based on the sequencing of ApeKI-digested libraries. Five AD-characterized phenotypes were used to assign animals to pairwise groups. Signatures of selection were detected using integrated measurement of fixation index (FST) and nucleotide diversity (θπ), that were validated by haplotype-based (hap-FLK) test. The total of 99 putatively selected regions harbouring 63 genes were detected in different groups. The gene ontology revealed numerous genes related to immune response (e.g. TRAF3IP2, WDR7, SWAP70, CBFB, and GPR65), liver development (e.g. SULF2, SRSF5) and reproduction process (e.g. FBXO5, CatSperß, CATSPER4, and IGF2R). The hapFLK test supported two strongly selected regions that contained five candidate genes related to immune response, virus-host interaction, reproduction and liver regeneration. This study provided the first map of putative selection signals of response to AMDV infection in American mink, bringing new insights into genomic regions controlling the AD phenotypes.

Development of an antigen-capture enzyme-linked immunosorbent assay for diagnosis of Aleutian mink disease virus.

Aleutian mink disease (AMD), caused by Aleutian mink disease virus (AMDV), is a very important infectious disease of mink. Currently, elimination of antibody- or antigen-positive animals is the most successful strategy for eradicating AMD, but the claw-cutting method of blood sampling is difficult to perform and painful for the animal. In this study, we aimed to establish an antigen capture enzyme-linked immunosorbent assay (AC-ELISA) method for the efficient detection of AMDV antigens using fecal samples. A purified mouse monoclonal antibody (mAb) was used as the capture antibody, and a rabbit polyclonal antibody (pAb) was used as the detection antibody. The assay was optimized by adjusting a series of parameters. Using a cutoff value of 0.205, the limit of detection of the AC-ELISA for strain AMDV-G antigen was 2 µg/mL, and there was no cross-reaction with other mink viruses. The intra- and inter-assay standard deviations were below 0.046, and the correlation of variance (CV) values were 1.24-7.12% when testing fecal samples. Compared with conventional PCR results, the specificity and sensitivity were 91.5% and 90.6%, respectively, and the concordance rate between the two methods was 91.1%.

Dietary supplementation of Ascophylum nodosum improved kidney function of mink challenged with Aleutian mink disease virus.

BACKGROUND: Feed additives which can ease the negative effects of infection by the Aleutian mink disease virus (AMDV) are of interest to mink farmers. The effects of kelp meal (Ascophylum nodosum) supplementation on immune response, virus replication and blood parameters of mink inoculated with AMDV were assessed. AMDV-free black mink (n = 75) were intranasally inoculated with a local strain of AMDV and fed a commercial pellet supplemented with kelp meal at the rates of 1.5% or 0.75% of the feed or were kept as controls (no kelp) for 451 days. Blood was collected on days 0 (pre-inoculation), 31, 56, 99, 155, 366 and 451 post-inoculation (dpi). RESULTS: No significant difference was observed among the treatments for the proportion of animals positive for antibodies against the virus measured by the counter-immunoelectrophoresis (CIEP), viremia measured by PCR, antibody titer measured by quantitative ELISA, total serum protein measured by a refractometer or elevated levels of gamma globulin measured by iodine agglutination test at the sampling occasions. At the termination of the experiment on 451 dpi, there were no differences among treatments for antibody titer measured by CIEP, total serum protein, albumin, globulins, albumin:globulin ratio, alkaline phosphatase, gamma-glutamyl transferase, and proportions of PCR positive spleen, lymph node or bone marrow samples, but blood urea nitrogen and creatine levels were significantly lower in the 1.5% kelp supplemented group than in the controls. CONCLUSION: Kelp supplementation improved kidney function of mink infected with AMDV with no effect on liver function, immune response to infection by AMDV or virus replication.

Dose response of black American mink to Aleutian mink disease virus.

INTRODUCTION: Aleutian mink disease virus (AMDV) causes a serious health problem for mink globally. The disease has no cure nor an effective vaccine and selection for tolerance using antibody titer is adopted by many mink farmers. The objective of this study was to investigate the effects of various doses of a local AMDV isolate on the response of black American mink to infection with AMDV. METHODS: Eight black American mink were each inoculated intranasally with 0.5 mL of eight serial 10-fold dilutions (100 to 10-7 ) of a 10% spleen homogenate containing a local AMDV isolate. Blood samples were collected on days 0, 20, 35, 56, 84, 140, and 196 postinoculation (dpi). Anti-AMDV antibodies and viral DNA were tested by counter-immunoelectrophoresis (CIEP) and PCR, respectively. Animals that were PCR or CIEP positive at 196 dpi (n = 41) were killed at 218 dpi, and samples of blood and seven organs were tested by CIEP and PCR. RESULTS: Antibody production persisted in all seroconverted mink until the termination of the experiment, whereas 71.1% of the mink showed short-lived viremia. Significant associations were observed between inoculum dose and the incidence of viremia until 84 dpi which disappeared thereafter, whereas associations between inoculum dose and the incidence of seropositive mink were significant on all sampling occasions. Antibody titer at 218 dpi significantly decreased with decreasing inoculum dose. AMDV DNA was detected in the bone marrow, lymph nodes, and spleen samples of almost all mink inoculated at every dose but was not detected in other organs of some mink. CONCLUSIONS: CIEP is more accurate than PCR for detecting AMDV infection in mink. Using antibody titer in naturally infected mink may not be accurate for the identification of tolerant mink.

Genetic diversity and phylogenetic analysis of Aleutian mink disease virus isolates in north-east China.

Aleutian mink disease is the most important disease in the mink-farming industry worldwide. So far, few large-scale molecular epidemiological studies of AMDV, based on the NS1 and VP2 genes, have been conducted in China. Here, eight new Chinese isolates of AMDV from three provinces in north-east China were analyzed to clarify the molecular epidemiology of AMDV. The seroprevalence of AMDV in north-east China was 41.8% according to counterimmuno-electrophoresis. Genetic variation analysis of the eight isolates showed significant non-synonymous substitutions in the NS1 and VP2 genes, especially in the NS1 gene. All eight isolates included the caspase-recognition sequence NS1:285 (DQTD↓S), but not the caspase recognition sequence NS1:227 (INTD↓S). The LN1 and LN2 strains had a new 10-amino-acid deletion in-between amino acids 28-37, while the JL3 strain had a one-amino-acid deletion at position 28 in the VP2 protein, compared with the AMDV-G strain. Phylogenetic analysis based on most of NS1 (1755 bp) and complete VP2 showed that the AMDV genotypes did not cluster according to their pathogenicity or geographic origin. Local and imported ADMV species are all prevalent in mink-farming populations in the north-east of China. This is the first study to report the molecular epidemiology of AMDV in north-east China based on most of NS1 and the complete VP2, and further provides information about polyG deletions and new variations in the amino acid sequences of NS1 and VP2 proteins. This report is a good foundation for further study of AMDV in China.

Identification and characterization of a novel B-cell epitope on Aleutian Mink Disease virus capsid protein VP2 using a monoclonal antibody.

Aleutian mink disease is caused by a highly contagious parvovirus (Aleutian mink disease virus, AMDV). This disease is one of the most commercially important infectious disease worldwide and causes considerable economic losses to mink farmers. The capsid protein VP2 is the major immunogenic antigenic protein of AMDV, and is involved in viral tropism, pathogenicity, and host selection. However, few reports have described the use of VP2-specific monoclonal antibodies (mAbs) in B-cell epitope identification and immunological detection. In this study, we produced a specific mAb, 1G5, against AMDV VP2 protein (amino acids: 200 ∼ 588) and characterized its specificity and relative affinity. Six partially overlapping truncated recombinant proteins and seven synthetized peptides were used to identify the epitopes recognized by 1G5. The results indicate that mAb 1G5 can distinguish AMDV, MEV and CPV2 with high affinity (Ka = 5.37 × 109), and the minimal linear epitope is located in amino acid residues 459EEEGWPAASGTHFED473. Sequence alignments demonstrated that the linear epitope was completely conserved among most Amdoparvoviruses except the bat parvovirus, where three substitutions (463W-463F, 466A-466G and 471F-471Y) were noted. Our results reveal that the identified epitope might be a common B-cell epitope of AMDV antibodies, and the 1G5 mAb can be used to identify the cleavage of the capsid proteins during AMDV infection. This is also the first report of a B-cell epitope on AMDV capsid protein VP2 (VP2: 459-473) using a mAb. These findings have potential applications in the development of new diagnostic tools for AMDV.

Accuracy of enzyme-linked immunosorbent assays for quantification of antibodies against Aleutian mink disease virus.

There is a growing interest among mink ranchers to select their stock for tolerance to the Aleutian mink disease virus (AMDV). Enzyme-linked immunosorbent assays (ELISA) are used to identify mink which have low anti-AMDV antibody titres and are expected to tolerate the AMDV infection. The objective of this study was to calculate the accuracy of three ELISA systems which were performed on blood or serum of AMDV-inoculated American mink (Neovison vison) at five laboratories in Canada, USA, Finland, the Netherlands and Denmark. The accuracy was determined by comparing the ELISA results with antibody titres measured by the counter-immunoelectrophoresis (CIEP) using 10 two-fold serial dilutions of the plasma. Antibody titres of 880 black mink which were inoculated with a spleen homogenate from a naturally infected mink were measured between 16 and 176 weeks post-inoculation. Each ELISA result from every laboratory covered a wide range of antibody titres and the Spearman's rank correlation coefficients between CIEP and ELISA results from different laboratories varied between 0.41 and 0.83, indicating a low to moderate accuracy of ELISA systems for ranking mink by antibody titre. The recombinant VP2-based ELISA used in the Netherlands and Finland ranked the mink by antibody titres more accurately than did the AMDV-G-based ELISA platforms developed in Denmark and the USA, suggesting that the source of antigen was one of the factors affecting the accuracy of ELISA results. It was concluded that the ELISA systems, particularly those based on AMDV-G antigen, require further refinement to improve their accuracy for ranking mink by antibody titre.

Identification of a novel Aleutian mink disease virus B-cell epitope using a monoclonal antibody against VP2 protein.

Aleutian mink disease virus (AMDV) is a parvovirus that causes an immune complex-mediated disease in minks. Capsid protein VP2 is a major structural viral protein and can be used to diagnose AMDV. In this study, a specific monoclonal antibody, 1M13, was produced against the AMDV VP2 protein (amino acids 291-502). A linear VP2-protein epitope was identified by subjecting a series of partially overlapping synthesized peptides to be enzyme-linked immunosorbent assay (ELISA) analysis. The results indicated that (386)HLQQNFSTRYIYD(398) was the minimal linear epitope that could be recognized by mAb 1M13. ELISA assays revealed that mink anti-AMDV sera could also recognize the minimal linear epitope. Sequence alignments demonstrated that the linear epitope is highly conserved among AMDV strains except (386)H and is less conserved among Raccoon dog amdovirus, Gray fox amdovirus, Red fox amdovirus, Bat parvovirus and Mink enteritis parvovirus. Taken together, the generation of this VP2-specific mAb with a defined linear peptide epitope may have potential applications in the development of suitable diagnostic techniques for AMDV.

PREVALENCE OF ANTIBODY TO ALEUTIAN MINK DISEASE VIRUS IN EUROPEAN MINK (MUSTELA LUTREOLA) AND AMERICAN MINK (NEOVISON VISON) IN SPAIN.

The European mink (Mustela lutreola) has undergone a dramatic decline and is one of the most endangered mammals in the world. The invasive American mink (Neovison vison) is considered the main factor for this decline. However, the American mink's introduction and the subsequent ecological concurrence of the two species cannot solely explain the decline or disappearance of the European mink. Aleutian mink disease virus (AMDV) is the main health problem in fur farming worldwide, causing varied clinical syndromes that depend on the viral strain and host factors. Infection with AMDV has been speculated to contribute to the decline of the European mink, but a detailed study has not been performed. To assess the potential effects of AMDV infection on the conservation of the European mink, we surveyed AMDV antibody in samples from 492 native European mink and 1,735 feral American mink collected over 16 yr. The antibody prevalence in European mink was 32%. There were no statistically significant differences in antibody prevalence between sexes, among years, or among weight classes. For recaptured European mink, incidence of seroconversion (negative to positive) was 0.46 cases per animal-year at risk. For positive animals, the incidence of conversion from positive to negative was 0.18 cases per animal-year at risk. In 1,735 feral American minks, the overall prevalence was 32.4% and varied among the six wild populations studied. Infection with AMDV appears to be endemic, distributed across the entire ranges of both species, and no effects on the population dynamics of either species were observed.

[Research into the antibody detection technology of mink plasmacytosis and its current applications].

Mink plasmacytosis, caused by Aleutian Mink Disease Virus (AMDV), poses a threat to the development of the animal fur industry. Neutralizing antibodies against AMDV may result in a persistent infection rather than providing protection for minks. To date,no specific methods to prevent or cure this disease have been developed. In order to eliminate mink plasmacytosis, antibody detection technology has been used globally as a dominant approach to screen for AMDV-positive minks. This paper introduces the classical technology, counterimmunoelectrophoresis and emerging technology in terms of AMDV antibody detection,and provides a glimpse into the future development of these technologies.

Detection of Aleutian mink disease virus DNA and antiviral antibodies in American mink (Neovison vison) 10 days postinoculation.

Early detection of infection by the Aleutian mink disease virus (AMDV; Carnivore amdoparvovirus 1) by polymerase chain reaction (PCR) or counterimmunoelectrophoresis (CIEP) has important ramifications in virus eradication programs. A spleen homogenate containing a local isolate of AMDV was injected intraperitoneally into black (n = 44) and sapphire (n = 12) American mink (Neovison vison). Animals were euthanized 10 days postinoculation and anti-AMDV antibodies and AMDV DNA were tested in plasma and 7 organs by CIEP and PCR, respectively. Viral DNA was detected in the plasma, spleen, lymph nodes, bone marrow, and lung samples of all inoculated mink, but was not detected in some small intestine, kidney, and liver samples. In contrast, antibodies were detected in the plasma of 3 sapphire (25.0%) and 19 black (43.2%) mink but not in any of the organs. The sensitivity of the CIEP test on plasma samples was 39.3%, implying that low levels of antibodies during the early stages of virus exposure resulted in failure to detect infection by the CIEP test. We concluded that CIEP is not a reliable test for early detection of AMDV infection in mink and that there were considerable differences among mink of each color type for production of detectable levels of antibodies. PCR tests on samples of saliva, rectal swabs, and feces did not produce consistent and reliable results.

Aleutian mink disease virus in free-ranging mink from Sweden.

Aleutian mink disease (AMD) is a chronic viral disease in farmed mink and the virus (AMDV) has been found in many free-ranging mink (Neovison vison) populations in Europe and North America. In this study, AMDV DNA and AMDV antibodies were analysed in 144 free-ranging mink hunted in Sweden. Associations between being AMDV infected (defined as positive for both viral DNA and antibodies) and the weight of the spleen, liver, kidneys, adrenal glands and body condition were calculated and the sequences of ten AMDV isolates were analysed in order to characterize the genetic relationships. In total, 46.1% of the mink were positive for AMDV antibodies and 57.6% were positive for AMDV DNA. Twenty-two percent of the mink tested on both tests (n = 133) had dissimilar results. The risk of having AMDV antibodies or being positive for AMDV DNA clearly increased with age and the majority of the mink that were two years or older were infected. Few macroscopic changes were found upon necropsy. However, the relative weight of the spleen was sexually dimorphic and was found to be slightly, but significantly (p = 0.006), heavier in AMDV infected male mink than uninfected. No association between AMDV infection and body condition, weight of the kidneys, liver or adrenal glands were found. Several different strains of AMDV were found across the country. Two of the AMDV sequences from the very north of Sweden did not group with any of the previously described groups of strains. In summary, AMDV seems to be prevalent in wild mink in Sweden and may subtly influence the weight of the spleen.

[Eenie, Meenie, Miney, Moe, who is responsible for the antibody-dependent enhancement of Aleutian mink disease parvovirus infection?].

Aleutian mink disease parvovirus (AMDV) causes a persistent infection associated with immune complex disease, hypergammaglobulinemia, and high levels of antiviral antibodies. Despite the presence of an antibody, the virus is not cleared in vivo. Pre-existing antibodies may enhance viral infections, by Fc-receptor-mediated antibody-dependent enhancement (ADE), but the mechanism that underlies ADE has not been fully defined. Three models have been proposed, including: (1) interactions between antibody and FcR, complement C3 fragment and CR, or between C1q and C1qR, which promotes viral attachment to cells; (2) suppression of IFN-gamma-mediated host-cell antiviral gene expression by the upregulation of negative regulators of pathogen pattern recognition; and (3) the promotion of early IL-10 secretion. In addition, the role of cytokine IL-6 in ADE mediated disease development is discussed, to facilitate a better understanding of the pathogenesis of AMDV infection, as well as give insights into rational vaccine design approaches.

Validation of an automated ELISA system for detection of antibodies to Aleutian mink disease virus using blood samples collected in filter paper strips.

BACKGROUND: Aleutian mink disease virus (AMDV) is the cause of a chronic immune complex disease, Aleutian disease (AD), which is common in mink-producing countries. In 2005, implementation of an AMDV eradication programme in Finland created a need for an automated high-throughput assay. The aim of this study was to validate an AMDV-VP2 -recombinant antigen ELISA, which we developed earlier, in an automated assay format for the detection of anti-AMDV antibodies in mink blood and to determine the accuracy of this test compared with the reference standard (counter-current immunoelectrophoresis, CIEP). METHODS: A blood sampling method based on filter paper 12-strips (blood combs) and a device to introduce these strips to an ELISA plate for elution of the samples were developed. Blood and serum samples were collected from 761 mink from two farms with low (2%) and high (81%) seroprevalences of AMDV infection in 2008. ELISA sensitivity and specificity were estimated with a Bayesian 2-test 2-population model that allowed for conditional dependence between CIEP and ELISA. Agreement between the two tests was assessed with kappa statistic and proportion agreement. RESULTS: The sensitivity and specificity of the automated ELISA system were estimated to be 96.2% and 98.4%, respectively. Agreement between CIEP and ELISA was high, with a kappa value of 0.976 and overall proportion agreement of 98.8%. CONCLUSIONS: The automated ELISA system combined with blood comb sampling is an accurate test format for the detection of anti-AMDV antibodies in mink blood and offers several advantages, including improved blood sampling and data handling, fast sample throughput time, and reductions in costs and labour inputs.

Monitoring chronic infection with a field strain of Aleutian mink disease virus.

Aleutian mink disease virus (AMDV) readily spread within farmed mink and causes chronic infections with significant impacts for welfare and economy. In the present study a currently circulating Danish AMDV strain was used to induce chronic experimental infection of farmed mink. PCR was used to detect viral DNA in full blood, organs, faeces and oro-nasal swabs weekly for the first 8 weeks and then biweekly for another 16 weeks after AMDV challenge inoculation of wild type mink. The mink (n=29) was infected and seroconverted 2-3 weeks after AMDV inoculation and AMDV antibodies persisted during the maximum experimental period of 24 weeks. Viraemia and faecal excretion of viral DNA was detected in the mink (n=29) at various and intermittent time intervals. Excretion of viral DNA in oro-nasal swabs was detected for 1-8 weeks in 21 mink. This highlights the risk of transmitting AMDV between infected farms. PCR was successfully used to detect viral DNA in organs 8, 16 and 24 weeks after AMDV inoculation with only minor differences between these weeks which is of diagnostic interest. This AMDV challenge model was also used to mimic natural infection of susceptible sapphire mink. Four of 6 sapphire mink were infected indirectly via the AMDV inoculated wild type mink whereas the other 2 sapphire mink remained uninfected.

DNA vaccination with the Aleutian mink disease virus NS1 gene confers partial protection against disease.

Aleutian disease virus (ADV) causes severe losses in mink. This happens in nature as well as in farms. In spite of several attempts to provide an efficient protective protein based vaccine, experiments have failed so far. Only partial protection has been obtained. The aim of this work was to construct and test a protective DNA vaccine based on the gene encoding for the ADV non-structural protein 1 (NS1) and to test this construct as a potential vaccine candidate against ADV infection or disease. First, the vaccine construct was tested by in vitro transfection studies. NS1 protein expression was found by immunofluorescent studies and the expected size of translated protein confirmed by Western blot. Then, 18 female mink were divided into three groups: a control group, a DNA vaccinated group, and a group which received DNA vaccine plus a boost with recombinant NS1 protein in the last immunization. After virus challenge, the two DNA vaccinated groups induced higher antibody levels in the first 23 weeks of the 32 week observation period. One month after virus challenge, the most interesting finding was, that the "DNA+protein" group exhibited a significantly higher percentage of CD8+ cells, when compared to the levels in the two other groups. This, we believe, indicate a memory CTL response created by the vaccination. Most CD8+ cells were found to contain interferon gamma as measured by FACS intracellular staining. Severity of Aleutian disease was judged by quantification of plasma gammaglobulin levels and mink death statistics. The findings let us to conclude, that the two DNA vaccinated groups of mink did show milder disease characteristics, but that the vaccine effect also in this trial could only be characterized as partial.

Cytokine profiles in adult mink infected with Aleutian mink disease parvovirus.

The aim of this study was to examine the levels of gamma interferon (IFN-gamma)-, interleukin 4 (IL-4)-, and IL-8-producing cells in peripheral blood mononuclear cells from mink infected with the Aleutian mink disease parvovirus (ADV). As expected, ADV-infected mink developed high plasma gamma globulin values (hypergammaglobulinemia) and enhanced quantities of CD8-positive (CD8(+)) cells in the blood during the infection. We quantified the percentages of IFN-gamma- and IL-4-positive lymphocytes and IL-8-positive monocytes up to week 38 after virus challenge. The results clearly indicated marked increases in the percentages of IFN-gamma- and IL-4-producing lymphocytes during ADV infection. The total number of IL-8-producing monocytes in the blood of ADV-infected mink stayed fairly constant during the infection. In order to characterize the phenotype of the cytokine-producing cells, we performed double-labeling fluorescence-activated cell sorter (FACS) experiments with CD8 surface labeling in one channel and cytokine intracellular staining in the other. We found that most IFN-gamma and IL-4 in ADV-infected mink was produced by CD8(+) cells, while in the uninfected mink, these cytokines were primarily produced by a cell type that was not CD8 (possibly CD4-positive cells). We also observed that IL-8 was almost exclusively produced by monocytes. All of the above findings led us to conclude that both Th1- and Th2-driven immune functions are found in mink plasmacytosis.

[Some molecular-biological and immunological aspects of Aleutian disease of mink]. / Nekotorye molekuliarno-biologicheskie i immunologichskie aspekty patogeneza Aleutskoi bolezni norok.

Information on the development of the infectious process in the Aleutian disease of minks (ADM) on the molecular level, are updated. In particular, the decisive role played by the ABM virus infection of the cells of the immune system (B lymphocytes, macrophages, follicular dendritic cells) and the possible involvement of the mechanism of the antibody-dependent aggravation of this infection are pointed out. In addition, the role of the weak ADM virus promoter p36, the immune status of minks and their age in the determination of the acute or "slow" character of the course of the disease are considered.