[Molecular epidemiological characterization of hypervirulent carbapenem-resistant Klebsiella pneumoniae in a hospital in Henan Province from 2020 to 2022].

Objective: The study investigated the clinical distribution, antimicrobial resistance and epidemiologic characteristics of hypervirulent Carbapenem-resistant Klebsiella pneumoniae (hv-CRKP) in a hospital in Henan Province to provide a scientific basis for antibiotic use and nosocomial infection prevention and control. Methods: A retrospective analysis of the clinical data from the cases was carried out in this study. Clinical data of patients infected with the CRKP strain isolated from the clinical microbiology laboratory of Henan Provincial Hospital of Traditional Chinese Medicine from January 2020 to December 2022 were retrospectively analyzed. A string test, virulence gene screening, serum killing, and a G. mellonella infection model were used to screen hv-CRKP isolates. The clinical characteristics of hv-CRKP and the drug resistance rate of hv-CRKP to twenty-five antibiotics were analyzed using WHONET 5.6. Carbapenemase phenotypic characterization of the hv-CRKP was performed by colloidal gold immunochromatographic assay, and Carbapenemase genotyping, multi-locus sequence typing (MLST) and capsular serotyping of hv-CRKP isolates were performed by PCR and Sanger sequencing. Results: A total of non-duplicate 264 CRKP clinical isolates were detected in the hospital from 2020 to 2022, and 23 hv-CRKP isolates were detected, so the corresponding detection rate of hv-CRKP was 8.71% (23/264). The hv-CRKP isolates in this study were mainly from the intensive care unit (10/23) and neurosurgery department (8/23), and the main sources of hv-CRKP isolates were sputum (10/23) and bronchoalveolar lavage fluid (6/23). The hv-CRKP isolates in this study were highly resistant to ß-lactam antibiotics, fluoroquinolones and aminoglycosides, and were only susceptible to colistin, tigecycline and ceftazidime/avibactam. The detection rate of the blaKPC-2 among 23 hv-CRKP isolates was 91.30% (21/23) and none of the class B and class D carbapenemases were detected. Results of MLST and capsular serotypes showed that ST11 type hv-CRKP was the dominant strain in the hospital, accounting for 56.52% (13/23), and K64 (9/13) and KL47 (4/13) were the major capsular serotypes. Conclusion: The hv-CRKP isolates from the hospital are mainly from lower respiratory tract specimens from patients admitted to the intensive care department and the drug resistance is relatively severe. The predominant strains with certain polymorphisms are mainly composed of the KPC-2-producing ST11-K64 and ST11-KL47 hv-CRKP isolates in the hospital.

[Constructions and advances of animal models of Pseudomonas aeruginosa infection].

Pseudomonas aeruginosa (P. aeruginosa) is an opportunistic pathogenic bacterium with complex pathogenesis and drug resistance mechanisms. It has high morbidity and mortality and can cause acute and chronic infections in immunocompromised individuals, with lung infections, wound infections, and bloodstream infections being the most common. The animal infection model of P. aeruginosa is of great value for in-depth research on the pathogenicity, drug resistance, and therapeutic measures of P. aeruginosa by simulating the pathways of human bacterial infections. This article firstly summarizes the selection, anesthesia, and disposal of experimental animals in the construction of animal models of P. aeruginosa infection, and then reviews the methods of construction, model evaluation, and applications of animal models of P. aeruginosa pulmonary infection, wound infection, and bloodstream infection, in order to provide a reference for scientific research related to P. aeruginosa infectious diseases.

[Sensitization characteristics of Juniperus chinensis pollen in Beijing area].

Objective: To investigate the sensitization characteristics of Juniperus chinensis pollen in patients with allergic rhinitis and/or allergic asthma in Beijing area, and to explore the characteristics of Juniper chinensis pollen sensitized population. Methods: Patients with suspected allergic rhinitis and/or asthma from January 2017 to December 2019 in the outpatient department of Allergy Department of Beijing Shijitan Hospital were selected in this study. Skin prick test (SPT) was performed with Juniper chinensis pollen allergen reagent to compare different age and disease allergen distribution, and to observe the sensitization characteristics of its population. All of the analyses were performed using SAS software version 9.4. Results: A total of 8 380 patients were enrolled in the end. The total positive rate of Juniper chinensis pollen SPT reached 49.92% (4 183/8 380). The positive rate of Juniper chinensis pollen SPT was highest in the 10-14 age group, reaching 60.99% (283/464). Compared with other age groups, there was a statistical difference (χ²=266.77, P<0.01). The SPT positive rate of patients aged less than 10 years increased with the increase of age, while the SPT positive rate of patients aged over 40 years decreased with the increase of age. Single Juniper chinensis pollen was less allergenic, accounting for about 25.05% (1 048/4 183), and the patients' age was (35.21±12.39) years. Regardless of single Juniper chinensis pollen or other pollen allergies, allergic rhinitis was the main disease. Among the patients with SPT positive Juniper chinensis pollen combined with other inhaled pollen allergens, willow pollen accounted for the first (74.99%). The positive rate of Juniper chinensis pollen was the highest in patients with single allergic rhinitis, accounting for 52.05% (3 797/7 295), and the rate in patients with single allergic asthma was the lowest, accounting for 17.49% (53/303), with statistically difference (χ²=138.99, P<0.01). Conclusions: Juniper chinensis pollen is highly sensitized in patients with allergic rhinitis and/or allergic asthma in Beijing . The positive rate of SPT is highest among 10-14 age group, most of which showed strong positive reaction, and allergic rhinitis is more common in Juniper chinensis pollen sensitization diseases.

[Research progress on virulence factors of hypervirulent Klebsiella pneumoniae].

Hypervirulent Klebsiella pneumoniae, short for hvKP, is a hypervirulent variant of classical Klebsiella pneumoniae, which accounts for serious infection in healthy people, exhibits strong pathogenicity, high mortality and poor prognosis. At present, hvkp is of high prevalence all over the world, and the infection rate shows a continuous upward trend, which brings great challenges to public health security and clinical treatment. This paper summarized the research progress on virulence factors of hvkp, such as capsular polysaccharides, siderophore, lipopolysaccharide, adhesins and recently discovered Type Ⅵ secreting system, and aimed to deepen the understanding and recognition of hvKP.

[Reoperation rate and related factors in patients with Crohn's disease].

Objective: To analyze the cumulative reoperation rate of postoperative Crohn's disease (CD) patients and investigate the operation reasons and the effects of drugs on surgical recurrence. Method: Patients with Crohn's disease who had undergone intestinal resection from January 2000 to March 2020 in Peking Union Medical College Hospital were enrolled. Patients were divided into reoperation and non-reoperation group according to whether they had a second operation. And the basic characteristics and the reasons for the primary and second operation were retrospectively analyzed. Meanwhile, patients were divided into low-risk reoperation group and high-risk group based on risk stratification. Kaplan-Meier methods were performed to analyze the cumulative surgical recurrence rate and to compare the recurrence rate in different risk stratification and chi-square tests was used to analyze the effects of different maintenance drugs on reoperation. Result: A total of 160 patients were enrolled in the study. There were 110 males and 50 females, and the age at first operation was (35.6±14.1) years old. There were 40 patients in the reoperation group and 120 patients in the non-reoperation group. According to univariate analysis, the proportion of male gender(P=0.030), penetrating phenotype(P<0.001), history of appendectomy before the primary surgery(P=0.035) and no postoperative maintenance therapy (P<0.001) were higher in surgical recurrence group. In terms of the operation reasons, intestinal obstruction accounted for the highest proportion in the primary operation (26.9%, 43/160), while the intestinal fistula was the most common reason for reoperation (42.5%, 17/40). After the primary surgery, the cumulative reoperation rates at 1, 3, 5 and 10 years were 5.9% (9 cases), 12.3% (17 cases), 21.8% (25 cases) and 37.6% (34 cases), respectively. The ten years cumulative reoperation rate of the high-risk group was 42.8% (31 cases), which was much higher than that of low-risk group (19.8%, 3 cases), and the difference was statistically significant (P=0.006). There was no statistically significant difference in the surgical recurrence rate of low-risk group patients(P=0.076)whether maintenance therapies were added or not, while the recurrence rate of high-risk group patients who did not receive maintenance therapy was higher than those who received immunosuppressant with or without (±) 5-aminosalicylic acid (ASA) (P=0.001) and biological agent±5-ASA (P=0.001), and the difference was statistically significant. Conclusion: Patients with CD are still at risk of reoperation after surgery. Immunosuppressive agents and biologics can prevent patients from reoperation in high-risk groups.

[The 489th case: acute kidney injury, gross hematuria, nephrotic syndrome].

Onset with fever and back pain, an 81-year-old man had sudden oliguria and progressively elevated serum creatine from normal range to 660 µmol/L within 1 week after receiving contrast agents, various antibiotics, and several nonsteroidal anti-inflammation drugs. Urine output recovered after supportive treatment. However, his serum creatinine level rose again soon after a temporary decline accompanied by gross hematuria with almost normal morphology, nephrotic proteinuria, and hypoalbuminemia. Renal biopsy revealed necrotizing glomerulonephritis. Methylprednisolone was intravenously administrated 500 mg per day for 3 days, followed by oral glucocorticoids and cyclophosphamide. Gradually the patient's serum creatinine descended to 144 µmol/L.

[Research progress on the regulation mechanism of Pseudomonas aeruginosa biofilm].

Pseudomonas aeruginosa is one of the common multidrug-resistant bacteria in the clinic. Because it can produce a "protective" biofilm, it can affect the penetration and killing efficacy of antibacterial drugs, leading to the formation of a persistent and persistent chronic infection in the host. Biofilms make Pseudomonas aeruginosa resistant to antibacterials and evasive to the host's immune system. Therefore, traditional conventional antibacterials are difficult to achieve effective bactericidal treatment. Understanding the process of P. aeruginosa biofilm formation and the regulatory mechanisms that affect biofilms can provide ideas and methods for our future research on new antibacterial drugs.

[Analysis on clinical features of patients with ulcerative colitis associated colorectal cancer].

Objective: To analyze the clinical features of ulcerative colitis associated colorectal cancer (UC-CRC). Methods: A total of 869 inpatients with Ulcerative Colitis (UC) in Peking Union Medical Hospital from January 1998 to January 2018 were continuously enrolled. Clinical data and the outcome of colorectal cancer (CRC) were collected via medical records and telephone follow-up. Chi-square test and logistic regression model were used to analyze the data. Results: There were 16 patients in 869 UC inpatients who were diagnosed with CRC during a period of 7 548 person years and the incidence rate of UC-CRC was 1.84%. Compared to UC inpatients without CRC, a longer course of disease (OR=1.087, 95% CI:1.046-1.129) , a lower usage rate of 5-Aminosalicylic Acid(5-ASA) (OR=0.218, 95% CI:0.052-0.915) and a higher incidence rate of intestinal stenosis (OR=16.533, 95% CI:3.824-71.478) were found in UC inpatients with CRC. Conclusions: A long disease course is a risk factor for UC patients developing CRC, while 5-ASA therapy can reduce the risk of suffering from CRC. For UC patients with intestinal stenosis, CRC should be warned for occurring.

[Epidemiology of allergic rhinitis in children in grassland of Inner mongolia].

Objective: To investigate the self-reported prevalence, clinical characteristics, complications of allergic rhinitis (AR) and the sensitization of outdoor air pollen allergens in children in the Inner mongolia grassland region. Methods: A multistage, stratified and random clustered sampling with a face-to-face interview survey study in children from 0 to 17 years old was performed together with 10 common allergen skin prick tests (SPT) and measurements of the daily pollen count in 6 regions in the Inner mongolia grassland region from May to August of 2015. SAS 9.4 software was used for data analysis. Results: A total of 2 443 subjects completed the study. The self-reported prevalence of AR was 26.6%. The prevalence of boys was higher than that of girls (28.8% vs 24.3%, χ(2)=6.157, P<0.05). Subjects from urban areas showed higher prevalence than rural areas (34.7% vs 18.8%, χ(2)=79.107, P<0.05). There was significant regional difference in the prevalence of AR among the six areas investigated (χ(2)=221.416, P<0.05). The main clinical symptoms of AR were sneezing (88.2%) and nasal congestion (78.6%). Among combined diseases, asthma accounted for 16.5% (107/650), rhinoconjunctivitis accounted for 47.9% (311/650). The peak season of AR was April and July, with the top SPT positive allergens of Artemisia species and chenopodium in this area. Conclusions: The prevalence AR in children in the Inner mongolia grassland region is extremely high. Sneezing is the main clinical symptom. Rhinoconjunctivitis is the most common combined disease. High summer and autumn pollen exposure is the main cause of AR.

Characterization of microbial community profiles associated with quality of Chinese strong-aromatic liquor through metagenomics.

AIMS: Microorganisms in fermentation pits (FPs) play key roles for Chinese-strong-aromatic-liquor (CSAL) production. However, the microbial community in the FPs is still poorly understood. Here, the aim of this study was to reveal the diversity and potential functions of microbiota in FPs. METHODS AND RESULTS: Sequencing-by-synthesis-based metagenomic sequencing and annotation results revealed that the microbiota of FPs was primarily composed of Firmicutes (54·6%), Euryarchaeota (15·3%), Bacteroidetes (10·1%), Gammaproteobacteria (5·8%), Opisthokonta (5·7%) and Unclassified_Bacteria (2·3%). And 133 genera were identified as the dominant genera of this fermentative food. Lactobacillus, Sedimentibacter, Syntrophomonas, Methanoculleus, Methanobacterium, Bacillus, Clostridium, Galactomyces, Candida, Pichia, Penicillium and Aspergillus were defined as active populations for biosynthesizing the characteristic volatile compounds of CSAL. The study also revealed that the microbial community structures changed significantly with different cellar ages and over different geographical regions. (i) The presence of Bacteroidetes was the most distinctive feature that characterized the different FPs ages. (ii) Distinct contents of Gammaproteobacteria and Euryarchaeota were observed at different positions in the FPs. (iii) Euryarchaeota markedly contributed to the generation of the character of the liquors with distinct geographical associations. CONCLUSIONS: This study demonstrated that the changes of microbial communities determined the different quality characteristics of CSAL. SIGNIFICANCE AND IMPACT OF THE STUDY: This research contributes to a deeper understanding of the FPs microbial composition and shows a new microbial resource for biotechnological applications.

[Immunometabolism and systemic lupus erythematosus].

Systemic lupus erythematosus (SLE) is a highly heterogeneous autoimmune disease, characterized by production of pathogenic autoantibodies and wide involvement of multiple systems. Damageofimmune tolerance and imbalance of immune homeostasis lead to the production of autoantibodies and the injuries of multiple organs and systems. In recent years, plenty of studies have identified that immunometabolism affects survival status of certain cells, also cell activation, differentiation and effector functions. Conversely, immune cells with different functions or differentiational status upregulate specific metabolic pathways to maintain their identities. In response to outer stimulations, naive immune cells differentiate into activated cells, accompanied with a series of immunometabolism changes. Therefore, abnormal immunometabolism can induce global imbalance of immune homeostasis, which further results in the initiation and development of autoimmune diseases, including SLE. Multiple abnormalities of immunometabolism have been found in patients with SLE or mouse models of lupus. Immune cells involved in the development of SLE, such as T cells, B cells, dendritic cells and macrophages present various metabolic abnormalities and pathological phenotypes. Among these cells, CD4+ T cells play predominant roles in the pathogenesis of SLE. Lots of studies demonstrated that CD4+ T cells and their subsets were in abnormal immunometabolic status,which further resulted in the development of SLE. In CD4+ T cells from patients with SLE or mouse models of lupus, both levels of glycolysis and oxidative phosphorylation are significantly higher compared with healthy controls. However,mitochondrial abnormalities, decreased ATP production and increased level of oxidative stress also have been found in these cells, which play important roles in the production of reactive oxygen intermediates and autoantibodies. Aggregated lipids rafts and increased synthesis of glycosphingolipid and cholesterol also have been observed in the CD4+ T cells from patients with SLE, leading to the abnormally elevated TCR signaling. Moreover, mechanistic target of rapamycin (mTOR) signaling is activated in the CD4+ T cells from both patients with SLE or mouse models of lupus and participate in the metabolic abnormalities of pathological CD4+ T cells. Progressive understanding of immunometabolism give us new insights of the pathogenesis of SLE and provide us with more therapeutic targets in the treatment of SLE.

MiR-129-5p is downregulated in breast cancer cells partly due to promoter H3K27m3 modification and regulates epithelial-mesenchymal transition and multi-drug resistance.

OBJECTIVE: In this study, we firstly studied whether H3K27me3 modification is a mechanism of miR-129-5p downregulation in breast cancer and further investigated the functional role of miR-129-5p in epithelial-to-mesenchymal transition (EMT) and in multi-drug resistance (MDR) of the cancer cells. MATERIALS AND METHODS: Immunoprecipitation (IP) and Chromatin Immunoprecipitation (ChIP) assay were performed to detect the association among SOX4, EZH2 and H3K27me3 and their enrichment in the promoter region of miR-129-2. Western blot and immunofluorescent staining were performed to detect the expression of epithelial and mesenchymal markers. MTT assay was applied to test drug sensitivity. RESULTS: Enforced EZH2 and SOX4 expression resulted in suppressed miR-129-5p level in MCF-7 cells. There was an interaction among SOX4, EZH2 and H3K27me3 modification and they were significantly enriched in the region upstream of transcription start of miR-129-2. MCF-7 cells transfected with miR-129-5p mimics had significantly suppressed SOX4 expression. MCF-7 cells with miR-129-5p overexpression had significantly restored E-cadherin expression and suppressed N-cadherin and Vimentin expression. The drug sensitivity assay showed that miR-129-5p substantially reduced IC50 of ADM, VCR and PTX in MCF-7/ADM cells CONCLUSIONS: There is a reciprocal regulation between miR-129-5p and SOX4 via the SOX4/EZH2 complex mediated H3K27me3 modification in breast cancer cells. MiR-129-5p is an important miRNA modulating EMT and MDR in breast cancer cells.

Transcriptome analysis of potential simple sequence repeat markers in Ammopiptanthus mongolicus.

Ammopiptanthus mongolicus, an evergreen broadleaf legume shrub, can survive under conditions of high and low temperature, extreme salinity, and drought. This attribute makes it an ideal model for studying mechanisms of stress tolerance in plants. However, simple sequence repeat (SSR) resources for this species are insufficient in public databases. In this study, a total of 44,959 unigenes identified from the A. mongolicus transcriptome were used for SSR analysis by MIcroSAtellite (MISA). A total of 13,859 SSRs were found to be distributed within 10,409 unigenes, with an average length of 15 bp and an average density of one SSR per 4.4 kb. There were 222 different motif types in the A. mongolicus transcriptome, and mononucleotide repeats represented the main type, accounting for 44.2% of all SSRs. The (A/T)n repeat was the most frequent motif, accounting for 42.37% of all SSRs. We also performed Gene Ontology functional analysis, Kyoto Encyclopedia of Genes and Genomes database pathway analysis, and eggNOG analysis, and identified 6157, 2301, and 9845 unigenes containing SSRs in these three databases, respectively. The functional categorization of A. mongolicus unigenes containing SSRs revealed that these unigenes represent many transcribed genes with different functions. These data provide sequence information that may be used to improve molecular-assisted markers for the study A. mongolicus genetic diversity.

Antibacterial activity of ZnO nanoparticles with a modified surface under ambient illumination.

In various practical applications, nanomaterials typically have functionalized surfaces. Yet, the studies of toxicity and antibacterial activity of functionalized nanoparticles are scarce. We investigated the effect of surface modifications on antibacterial activity of ZnO under ambient illumination, and we found that nanoparticles coated with different surface modifying reagents could exhibit higher or lower toxicity compared to bare ZnO, depending on the surface modifying reagent used. Different surface modifying reagent molecules resulted in differences in the release of Zn(2+) ions and the production of reactive oxygen species (ROS). However, the antibacterial activity did not correlate with the ROS levels or the Zn(2+) ion release. One of the surface-modified ZnO samples exhibited significantly lower Zn(2+) ion release while at the same time exhibiting improved antibacterial activity. In all cases, damage of the cell wall membranes and/or changes in the membrane permeability have been observed, together with the changes in ATR-FTIR spectra indicating differences in protein conformation. Mechanisms of antibacterial activity are discussed.

Effect of suppression of TGF-beta1 expression on cell-cycle and gene expression of beta-1,4-galactosyltransferase 1 in human hepatocarcinoma cells.

beta-1,4-galactosyltransferase 1 (beta1,4-GT 1) is localized both in the Golgi complex where it catalyzes the transfer of galactose from UDP-galactose to terminal N-acetylglucosamine forming Galbeta1 --> 4GlcNAc structure, and on the cell surface where it serves as an adhesion molecule. It has previously been reported that the expression of beta1,4-GT 1 was cell-cycle-specific, regulated by cell growth. Transforming growth factor-beta1 (TGF-beta1) could regulate cell G1/S phase transition and modulate cell growth in many types of cells. In this study, we introduced the antisense-TGF-beta1 into SMMC-7721 cell, a human hepatocarcinoma cell line, for blocking its intrinsic TGF-beta1 expression, and changing its cell-cycle, and then analyzed the gene expression of beta1,4-GT 1 together with the beta1,4-GT activity. The result showed that the antisense-TGF-beta1 transfected SMMC-7721 cells (AST/7721) were growth enhanced, with more cells in S phase and less cells in G2/M phase compared with the mock transfected cells (pcDNA3/7721). At the same time, it was found that the gene expression of beta1,4-GT 1 in AST/7721 was decreased to one fifth that of pcDNA3/7721, and the cell surface beta1,4-GT activity was reduced to one fifth of the control, while the total activity of beta1,4-GT was decreased to one half that of the control. The results indicate that suppression of TGF-beta1 expression resulted in change of cell-cycle together with the decreased gene expression of beta1,4-GT 1 and beta1,4-GT activity in human hepatocarcinoma cells.

In situ hybridization of hepatitis B DNA in hepatitis B-associated glomerulonephritis.

Renal tissues from 43 of 49 children with hepatitis B virus-associated glomerulonephritis (HBV-GN) were examined for HBV DNA by in situ hybridization (ISH) assay within the last 10 years. HBV DNA was identified in 41 of the 43 cases (95.3%). HBV DNA was distributed generally in the nucleus and cytoplasm of epithelial cells and mesangial cells of glomeruli, and epithelial cells of renal tubules. HBV DNA also existed simultaneously in renal interstitial tissues in some of these cases. The positive results from HBV DNA ISH correlated well with HBV antigen assays. The analyses implied that the more extensive the existence of HBV DNA in the nephron unit and interstitial tissue, the more severe the clinical manifestation. The duration of proteinuria in cases with HBV DNA in renal tubules was much longer than in those with no HBV DNA in renal tubules. The persistence of the HBV genome or genes in the kidney could lead to the expression of viral antigens in renal tissues and might cause cellular pathological alteration. This would support utilization of antiviral therapy, such as cytokines, in the treatment of HBV-GN.

[Further study on the immunopathology of hepatitis B virus associated glomerulonephritis].

By using immunohistochemical techniques the deposition of HBV associated immune complexes was studied in 845 consecutive cases of renal biopsy. In 665 cases of primary glomerulonephritis the frequencies of HBsAg, HBeAg and HBcAg detection in glomeruli were 11.9%, 8.3% and 3.2% respectively with a total HBV antigen positive frequency of 12.2%. High positive rates were found in membranous glomerulonephritis (MGN, 37.1%), mesangioproliferative GN (MPGN, 26%) and IgA nephropathy (IgA-NP, 18.9%). The detection of HBV infection markers in serum were simultaneously performed in 213 cases; 31.7% of the patients with primary GN were found to be positive. In patients with positive HBV infectious markers in the serum, deposits of HBV antigens in glomeruli were found in 49.1% of the cases. The incidence was significantly different in the serum negative group (10.6%). Meanwhile, about 68.3% of the cases with HBV antigen deposits in the kidney was found to have positive HBV markers in the serum. Also the incidence was significantly different in the group without HBV antigen deposits in the kidney (20.9%). It was again confirmed that the pathogenesis of hepatitis B virus associated glomerulonephritis (HBV-GN) was related to the deposition of HBV immune complexes in kidney tissue. It was noticed that the deposition of three different types of HBV antigens was somewhat associated with the development of specific forms of HBV GN. The diagnostic criteria of HBV-GN were discussed in detail.

[Immunohistochemical study of the expression of major histocompatibility complex (MHC)-determined antigens in renal tissue of MRL/lpr mice].

Expression of MHC antigens in renal tissue of MRL/lpr(H-2K) mice were demonstrated by monoclonal antibodies against class I(KK) and class II(IAK) antigens and ABC immunoperoxidase method. The expression of KK antigen in glomeruli, tubules and vessels of kidney and IAK antigen in glomeruli tubules was stronger in mice fed with beef tallow diet after gamma-interferon treatment than in the control group. This result suggests that using of gamma-interferon may enhance the presentation of MHC antigens in renal tissue of MRL/lpr mice. In mice raised with Menhaden fish oil diet after gamma-interferon treatment, however, the enhancement of expression of IAK antigen was detected only in renal tubules. In comparing with mice fed with beef tallow after gamma-interferon injection, the expression of KK antigen in glomeruli, vessels and IAK in the dendritic cells of renal interstitium was weaker in mice fed with fish oil. This result indicates that fish oil can more or less inhibit the expression of MHC antigens in renal tissue of mice. The mechanism of the inhibitory action of fish oil remains to be elucidated.