[Study on specific cellular immunity of enhance intracellular survival antigen of Mycobacterium tuberculosis in patients with pulmonary tuberculosis]

OBJECTIVE

To investigate the level of specific cellular immunity in patients with active pulmonary tuberculosis and its potential relationship with severity of the disease.

METHODS

Thirty active pulmonary tuberculosis patients with positive tubercle bacilli in sputum were enrolled for the study. Immune responses including lymphocytes proliferation enhanced by enhance intracellular survival (EIS) antigen and cytokine production including interferon-gamma (IFN-gamma) and interleukin-10 (IL-10), were assayed. Cell proliferation was determined by methyl thiazolyl tetrazolium (MTT), while cytokine production was quantified by enzyme linked immunoadsorbent assay (ELISA). The results were compared to those of 20 healthy individuals and 16 persons recovered from tuberculosis.

RESULTS

Cell proliferation response and IFN-gamma production were significantly higher in patients convalescent from tuberculosis compared to patients with active pulmonary tuberculosis, EIS antigen was found to elicit a dominant Th2 cytokine response.

CONCLUSION

Impaired Th1 immune response to EIS is observed in patients with active pulmonary tuberculosis. Induction of imbalance of Th1/Th2 immune response may be the main action of EIS, which may be a factor of pathogenesis of tuberculosis.

Lymphoid Organ Size Varies Among Inbred Lines 63 and 72 and Their Thirteen Recombinant Congenic Strains of Chickens with the Same Major Histocompatibility Complex

The objective was to evaluate lymphoid organ size in chickens from a series of 13 recombinant congenic strains (RCS) and their highly inbred parental lines (6(3) and 7(2)). The parental line 6(3) was selected for resistance to tumors induced by Marek's disease virus and avian leukosis viruses, whereas line 7(2) was selected for susceptibility to these tumors. Each RCS on the average contains a random one-eighth of genome from the donor line 7(2). Previous studies have shown that lines 6(3) and 7(2) differ in the size of primary lymphoid organs; i.e., the bursa of Fabricius (BF) and the lobes of the thymus (T) are smaller in line 6(3) than line 7(2). In the current study, the relative size of the T, BF, and spleen was first examined in about 15 males from each of 13 RCS and the 2 parental lines at 60 to 69 d of age. The differences of relative BF, T, and spleen size among the RCS and the parental lines 6(3) and 7(2) differed significantly (P < 0.001). Males and females from 4 RCS and the 2 parental lines were evaluated a second time, and differences in the relative sizes in lymphoid organs among the RCS and parental lines were consistent. In 2 RCS, the size of the T and BF was comparatively large as in line 7(2), leading to the conclusion that different allelic forms at 1 or more loci in these RCS regulate the size of both organs. In 2 other RCS, the BF was large compared with the T, suggesting that allelic forms at some loci in these RCS influence the BF independent of the T. The relative lymphoid organ size among the RCS appeared to cosegregate with the concentration of IgG in the plasma measured previously. The evaluation of genomic variability of these lines is underway, and the RCS are available for research on traits that differ between lines 6(3) and 7(2).

Montmorillonite-Cu(II)/Fe(III) oxides magnetic material as adsorbent for removal of humic acid and its thermal regeneration

In this work, the adsorption features of montmorillonite and the magnetic properties of Cu(II)/Fe(III) oxides were combined in a material to produce magnetic adsorbent, which can be separated from the medium by a simple magnetic process after adsorption. The magnetic material is effective for the removal of humic acid. At pH 6.1, 96% removal was observed from 4.4 mg l(-1) humic acid solution containing 0.02 M NaCl. The adsorption is pH and ionic strength dependent. Adsorption is favored at lower pH values and dissolved NaCl can enhance the adsorption. The adsorption mechanism of humic acid to the magnetic material was suggested to be the ligand exchange reaction between carboxylic groups of humic acid molecules and the magnetic material surface. The magnetic material can be thermally regenerated. The temperature and time required to achieve good regeneration efficiency were determined to be 300 degrees C and 3 h, respectively. The regenerated adsorbent is still magnetic and approximately has as high specific saturation magnetization and good adsorption capacities as the as-prepared adsorbent.

[Hepatitis E virus of different genotypes contains multiple-type antigenic epitopes]

Monoclonal antibodies (McAbs) were prepared against a recombinant protein p166Us derived from US-1 strain of hepatitis E virus (HEV). The immune reactivity of the McAbs to seven p166s derived from different genotypes and subtypes of HEV, which included p166Bur (genotype I a), p166Pak (genotype I b), p166Mor (genotype I c), p166Mex (genotype II), p166Us (genotype III), p166Nz (swine HEV, genotype III) and p166Chn (genotype IV), was tested by an indirect enzyme-linked immunosorbent assay (ELISA) and a Western blotting assay. The immunological relationship between the McAbs and native HEV particles or anti-HEV positive serum samples was analyzed by an antigen-competitive or antibody-competitive ELISA. Totally, six McAb-producible hybridoma cell lines, designated by the name of 4D3, 2E3, 11E11, 12H5, 3A3 and 1F1 respectively, were cloned and obtained in this study. The McAb of 4D3 could react to all of the seven p166 recombinant proteins. This kind of reaction could be inhibited by each of 4 genotypes of native HEV particles or anti-HEV positive serum samples. The McAbs produced by 2E3, 11E11 and 12H5 reacted to p166Us, p166Nz and p166Chn, but did not react to p166Bur, p166Pak, p166Mor and p166Mex. The reaction of McAb of 2E3, as an example of the McAbs of 2E3, 11E11 and 12H5, could be only inhibited by genotype III and IV HEV or anti-HEV positive serum. The McAb of 3A3 could bind to p166Us as well as p166Nz. The McAb produced by 1F1 was reactive to the p166Us only. However, neither of I , II , IV genotype HEV particles or antisera could inhibit both of their reactions to p166Us. The data as mentioned above suggested that there are multiple-type antigenic epitopes such as genotype I, II, III and IV common, III and IV common, and III specific epitopes within HEV ORF2 encoded p166 proteins of different genotypes and subtypes of HEV. Moreover, the antigenic epitopes on recombinant protein p166s and these on native HEV particles possess identical immunological characteristics.

[Evaluation of Gd-BOPTA and Gd-DTPA in contrast-enhanced MR imaging of the liver]

OBJECTIVE

To evaluate the safety, tolerance and efficacy of Gd-BOPTA and Gd-DTPA in contrast-enhanced MR imaging of the liver.

METHODS

Forty-two patients having been suspected of suffering from primary liver tumor or hepatic metastasis by ultrasonography (US) or CT received Gd-BOPTA or Gd-DTPA in contrast-enhanced MRI examination pre- and post-contrast MRI. T(1)- and T(2)-weighted spin-echo, and T(1)-weighted gradient-echo images were acquired before injection. Dynamic T(1)-weighted gradient-echo images were obtained at 15 - 45 s, 1 - 2, 2 - 3, 4 - 5 and 8 min, respectively, after intravenous injection of Gd-BOPTA or Gd-DTPA at the same dose of 0.1 mmol/kg, and delayed T(1)-weighted spin-echo and gradient-echo images were acquired at 40 - 120 minutes after injection. All the images were assessed in three matched pairs including pre-contrast images vs. early post-contrast images; pre-contrast images vs. delayed post-contrast images; and pre-contrast images vs. early and delayed post-contrast images. The assessment was made in terms of 4 aspects including improved conspicuousness and/or delineation of liver lesions, improved confidence in lesion detection or exclusion, improved assessment of lesion internal morphology, and improved confidence in lesion characterization. The results of assessments were statistically compared inside every group or between two groups, and the radiological utility of contrast enhancement was also evaluated at the end of the study.

RESULTS

1. There were significant differences between pre-contrast images vs. early post-contrast images and pre-contrast images vs. delayed post-contrast images inside the Gd-DTPA group, and the early post-contrast images were superior to delayed images. 2. There were significant differences between the two groups in terms of pre-contrast images vs. delayed post-contrast images, and Gd-BOPTA was superior to Gd-DTPA. 3. The quality of post-contrast images were improved obviously with a rate of 72.7% for Gd-BOPTA and 70.0% for Gd-DTPA, respectively, but without significant difference.

CONCLUSION

The early post-contrast phase of Gd-DTPA-enhanced MR imaging is superior to delayed phase. The effects of Gd-BOPTA and Gd-DTPA in early post-contrast imaging are comparable, but Gd-BOPTA is significantly superior to Gd-DTPA in delayed post-contrast imaging.

Assessment of ancestry probabilities in the presence of genotyping errors

This paper extends an approach for estimating the ancestry probability, the probability that an inbred line is an ancestor of a given hybrid, to account for genotyping errors. The effect of such errors on ancestry probability estimates is evaluated through simulation. The simulation study shows that if misclassification is ignored, then ancestry probabilities may be slightly overestimated. The sensitivity of ancestry probability calculations to the assumed genotyping error rate is also assessed.

Purification and characterization of Mycobacterium tuberculosis indole-3-glycerol phosphate synthase

Indole-3-glycerol phosphate synthase (IGPS) plays an important role in the survival of Mycobacterium tuberculosis. The trpC gene, encoding IGPS, is essential for the growth of M. tuberculosis. It was expressed at the transcriptional level in cultured M. tuberculosis. The recombinant IGPS with an added His-tag was purified. The His-tag was found to have a small effect on the biochemical properties of IGPS. IGPS is a monofunctional enzyme in M. tuberculosis. Recombinant IGPS has considerable beta-pleated sheet and is relatively compact. The enzyme activity is significantly inhibited by denaturants and antibiotics, suggesting that IGPS may be a novel potential drug target of M. tuberculosis.

[Relationship between apoptosis of rat hippocampus cells induced by aluminum and the copy of the bcl-2 as well as bax mRNA]

OBJECTIVE

To explore the effects of aluminum chloride (AlCl3) on the apoptosis of rat hippocampus cells and the relationship between the apoptosis and the expression of the bcl-2 as well as bax mRNA.

METHODS

40 SD rats, adult and healthy, were divided into 4 groups randomly: normal saline, Al3+ 2.5 mg/kg, 5 mg/kg, 10 mg/kg. They were exposed to AlCl, by intraperitioneal injection at the dose of 0.2 ml/d for 60 days. After exposure, the apoptosis of hippocampus cells were measured by method of TUNEL. The expression of bcl-2 mRNA and bax mRNA in rats' hippocampus were measured by RT-PCR. The results were analyzed by the gelatum analyzing system.

RESULTS

The rates of apoptosis in hippocampus cells in Al3+ 5 mg/kg group and Al3+ 10 mg/kg group were significantly higher than that of controls (P < 0.05). But Al3+ 2.5 mg/kg group was not significantly higher than that of control (P > 0.05), and was significantly decreased in hippocampus cells in Al3+ 5 mg/kg and 10 mg/kg group compared with the control group (P < 0.05). The expression of bcl-2 mRNA was significantly decreased in every aluminum treatment group compared with the control group (P < 0.05). The expression of bax mRNA was significantly increased in every aluminum treatment group compared with the control group (P < 0.05). There was negative correlation between AI and the expression of Bcl-2 (r = -0.909, P < 0.01). There was positive correlation between Al and the expression of Bax (r = 0.871, P < 0.01).

CONCLUSION

Aluminum can induce apoptosis in rat hippocampus cells through the downwards regulation of bcl-2 mRNA, the upwards regulation of bax mRNA expression.

Specific antihepatocellular carcinoma T cells generated by dendritic cells pulsed with hepatocellular carcinoma cell line HepG2 total RNA

Dendritic cell (DC) vaccination with the use of total tumor RNA provides the potential to generate a polyclonal immune response to multiple known and unknown tumor antigens without HLA restriction. Our study evaluated this approach as potential immunotherapy for patients with hepatocellular carcinoma (HCC). Immature DCs generated from peripheral blood mononuclear cells of patients with HCC were transfected with HepG2-GFP (HepG2 cells transfected stably with plasmid pEGFP-C3) cells total RNA. Transfected, matured DCs were used to stimulate autologous T cells. Results revealed that DCs transfected with HepG2-GFP cells total RNA expressed EGFP when observed by flow cytometry. Compared with those before transfection, the expressions of membrane molecules were increased dramatically, and interleukin-12p70 release in the supernatant was elevated significantly. Specific T cells generated by DCs transfected with HepG2-GFP total RNA recognized HLA-matched HepG2 cell lines specifically. These findings indicate that these RNA-transfected DCs successfully generate specific T cells that specifically recognize HCC cells. Total tumor RNA-pulsed DCs may have potential as an adjuvant immunotherapy for patients with HCC.

[Regulation effects of tourmaline on seawater pH value]

In this paper, chemical analysis, X-ray diffraction and atomic force microscopy were employed to examine the characteristics of tourmaline produced in east Inner Mongolia Autonomous Region, and batch experiments were conducted to study its regulation effects on seawater pH value. The factors affecting the regulation, such as the dosage of tourmaline and the salinity and initial pH value of seawater, were also studied. The results showed that tourmaline could regulate the seawater pH value from its initial 3 and 10 to 7.1 and 8.9, respectively, and the regulation effect was greater in the seawater with lower salinity, e.g., after 120 minutes treatment, the initial pH value (5.0) of the seawater with a salinity of 5, 10, 15, 20 and 35 was increased by 3.24, 3.16, 3.06, 2.99 and 2.85 unit, respectively. Tourmaline had little effect on seawater conductivity. This study would provide an experimental base for the application of tourmaline in aquaculture.

Development and validation of a PCR-RFLP assay to evaluate TVB haplotypes coding receptors for subgroup B and subgroup E avian leukosis viruses in White Leghorns

The cellular receptor of subgroup B avian leukosis virus (ALVB) is encoded by a gene at the tumour virus B (TVB) locus. TVB alleles encode specific receptors permitting infection by exogenous ALVB or avian leukosis virus subgroup D (ALVD) as well as endogenous avian leukosis virus subgroup E (ALVE), and thus susceptibility is dominant to resistance. Two single nucleotide polymorphisms at the TVB locus have been reported distinguishing three TVB alleles (TVB*S1, TVB*S3 and TVB*R). We have developed a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay using the two single nucleotide polymorphisms to define three observed allelic haplotypes and to identify the six possible TVB genotypes consisting of the three haplotypes in defined laboratory strains of chickens. One additional potential allelic haplotype and four genotypes were also briefly discussed. Chickens from parents heterozygous for different TVB alleles were challenged with Rous sarcoma viruses of subgroup ALVB and ALVE to induce wing-web tumours. Tumour incidences were evaluated between chickens of the genotypes determined with this newly developed PCR-RFLP assay. Importantly, chickens typed with this assay as TVB*S3/*S3 were resistant to infection by ALVE only, and those TVB*R/*R were resistant to both ALVE and ALVB. Furthermore, a vast majority of chickens with the susceptible TVB*S1/- genotypes developed a tumour. This PCR-RFLP assay enables a relatively rapid assessment of all six anticipated TVB genotypes in experimental strains of chickens undergoing segregation for TVB*S1, TVB*S3, and TVB*R alleles. This non-infectious assay should be further evaluated for the capacity to select and breed commercial chickens for genetic resistance to infections by ALVB, ALVD and ALVE.

The Influence of Mycobacterium tuberculosis sigma factors on the promotion efficiency of ptpAt promoter in Mycobacterium smegmatis

It was found in a previous study that Mycobacterium tuberculosis protein tyrosine phosphatase ptpAt promoter is a highly active promoter in slow-growing species of mycobacteria, such as M. tuberculosis and M. bovis BCG, but inert in fast-growing mycobacterial species, such as M. smegmatis. This difference is presumed to be due to the differences between sigma factors systems of slow-growing pathogenic mycobacteria and the fast-growing saprophyte M. smegmatis. Therefore, we constructed a series of plasmids, named pOLYG-13x, which can express various M. tuberculosis sigma factors and also contain a P(ptpAt)-gfp reporter gene construct. By inducing different sigma factor genes of M. tuberculosis in M. smegmatis, we were able to explore the influences of various sigma factors on the expression efficiency of the ptpAt promoter. The result show that of the 10 sigma factors evaluated, only sigF and sigL were able to weakly drive the ptpAt promoter in M. smegmatis and other sigma factors were unable to drive the promoter.

Retrospective evidence that the MHC (B haplotype) of chickens influences genetic resistance to attenuated infectious bronchitis vaccine strains in chickens

Infectious bronchitis is a respiratory disease of chickens that is caused by the coronavirus infectious bronchitis virus (IBV). Virtually all broiler and layer breeder flocks are routinely vaccinated against IBV. Two hatches of 1-day-old chicks from four lines were mistakenly vaccinated for infectious bronchitis using a moderately attenuated vaccine designed for chicks of an older age. The vaccination resulted in high mortality, and chicks from three of four lines died with signs typical of infectious bronchitis. The mortality that occurred using this less-attenuated vaccine was significantly influenced by the genetic line, and the MHC (B) haplotype in chickens of three B congenic lines. B congenic chickens possessing the B*15 haplotype were resistant in contrast to chickens possessing the B*13 or B*21 haplotypes. Chicks from two further hatches of the four lines were vaccinated appropriately with a more attenuated IBV vaccine, and only limited chick mortality was seen. These retrospective data from two repeated hatches confirm earlier data indicating chicken genes influence resistance to IBV, and indicate for the first time that genes tightly linked to the B haplotype are relevant in resistance to IBV. Due to extenuating circumstances it was not possible to verify results with chicks from F2 matings. Factors that may enhance definition of the role of the B haplotype in immune response to IBV, and the desirability for further analysis of a B haplotype-linked influence on immunity to IBV are discussed.

Heterodimeric interaction and interfaces of S100A1 and S100P

With the widespread use of yeast two-hybrid systems, many heterodimeric forms of S100 proteins have been found, although their biological significance is unknown. In the present study, S100A1 was found to interact with another S100 protein, S100P, by using the yeast two-hybrid system. The binding parameters of the interaction were obtained using an optical biosensor and show that S100P has a slightly higher affinity for S100A1 (K(d)=10-20 nM) when compared with that for self-association (K(d)=40-120 nM). The physical interaction of S100A1 and S100P was also demonstrated in living mammalian cells using a fluorescence resonance energy transfer technique. Preincubation of recombinant S100P with S100A1, before the biosensor assay, reduced by up to 50% the binding of S100P to a recombinant C-terminal fragment of non-muscle myosin A, one of its target molecules. Site-specific mutations of S100P and S100A1, combined with homology modelling of an S100P/S100A1 heterodimer using known S100P and S100A1 structures, allowed the hydrophobic interactions at the dimeric interface of the heterodimer to be defined and provide an explanation for the heterodimerization of S100P and S100A1 at the molecular level. These results have revealed the similarities and the differences between the S100P homodimer and the S100A1/S100P heterodimer.

Molecular cloning and characterization of a novel adenylate kinase 3 gene from Clonorchis sinensis

Adenylate kinase (AK) is a ubiquitous enzyme that contributes to the homeostasis of adenine nucleotides in living cells. AK catalyzes reversible high energy phosphoryl transfer reactions between ATP (or GTP) and AMP to generate ADP (or GDP). From a Clonorchis sinensis adult worm cDNA library, we isolated a cDNA clone encoding a novel AK3 isozyme. The 956 bp cDNA encodes a putative protein of 228 amino acids with a predicted molecular mass of 26.2 kDa. The recombinant CsAK3 protein produced in Escherichia coli can be refolded into a functional protein with AK3 activity. The optimum pH and temperature for the enzyme are 8.5 and 40 degrees C, respectively. The calculated activation energy is 56.04 kJ mol-1. The Km of the CsAK3 for AMP and GTP are 118 microM and 359 microM, respectively. CsAK3 is inhibited by Ap5A (>70% inhibition by 2.0 mM AP5A). Ap5A may be a potential lead compound acting on C. sinensis in which AK3 as a drug target.

Identification and characterization of class 1 integron resistance gene cassettes among Salmonella strains isolated from healthy humans in China

Twenty-three strains of Salmonella spp. isolated from healthy humans in Guangdong, China, were examined for their susceptibility to ten common antibiotics and the presence of antibiotic resistance integrons. All the strains were resistant to at least one antibiotic, and 4 strains were positive for the intI1 gene. Polymerase chain reaction using in-F and in-B primers showed the existence of amplicons of 1,009 bp in two, 1,664 bp in one, and 1,009 bp and 1,664 bp in one of the intI1 -positive isolates, respectively. Sequence analysis revealed that the 1,009-bp amplicon harbored gene cassette aadA2, conferring resistance to spectinomycin, and the 1,664-bp amplicon harbored genes aadA5 and dfr17, conferring resistance to spectinomycin, streptomycin and trimethoprim. Meanwhile the experiments of plasmid conjugation and Southern hybridization with intI1 as the DNA probe indicated that all the integrons found in these strains were chromosomal. Because the strains carrying class 1 integrons were isolated from healthy humans, it suggests the need for all-round surveillance of the antibiotic resistance of pathogens.

Zirconia pillared montmorillonite for removal of arsenate from water

Zirconia pillared montmorillonite, a clean adsorbent with increased specific areas of 40.118 m2/g and high basal spacing of 2.20 nm, was prepared for the removal of arsenate from water. Zirconia pillared montmorillonite is effective for the removal of arsenate. Adsorption is favored under acid conditions. Ca2+ and Mg2+ in the solution slightly enhance the adsorption. Over 95% removal was observed under natural pH conditions from 20 mg/L arsenate solutions containing 5.0 mg/L Ca2+ or Mg2+. High adsorption capacity of over 120 mg/g was observed from arsenate solutions with different Ca2+ concentrations. The Freundlich model can describe the adsorption equilibrium data well. The column test shows that the column allows the passage of the feeding solution for approximately 225 times the bed volume if the removal percentage of arsenate was monitored not to be lower than 98%. The adsorbed arsenate can be desorbed with NaOH and the desorption efficiency reaches 85% and 88% when the concentration of NaOH reaches 0.2 and 0.5 mol/L. Zirconia pillared montmorillonite can be regenerated and the regenerated adsorbents still have good adsorption capacities.

GeneContent: software for whole-genome phylogenetic analysis

GeneContent is a software system to infer the genome phylogeny based on an additive genome distance that can be estimated from the extended gene content data, which contains the genome-wide information (absence of a gene family, presence as single copy or presence as duplicates) across multiple species. GeneContent can also be used to explore the genome-wide evolutionary pattern of gene loss and proliferation.

AVAILABILITY

Distribution packages of GeneContent for both Microsoft Windows and Linux operating systems are available at http://xgu.zool.iastate.edu

CONTACT

xgu@iastate.edu.

[Intracranial metastasis of malignant tumors: clinical characteristics and MR imaging features]

OBJECTIVE

To study the clinical characteristics and MR imaging features of intracranial metastasis from malignant tumors.

METHODS

1271 patients who had history of primary tumor and suspected of cranial metastasis had MRI on Philips Gyroscan T5-NT MR scanner. The sequences included pre-contrast T(1)WI, FLAIR, and postcontrast transversal, sagittal, and coronal T(1)WI. All of the clinical data and MRI features of the patients were recorded and analyzed.

RESULTS

Of 547 patients with intracranial metastasis, 393 came from lung cancer (71.9%), 10% of 547 patients were found to have the presenting symptoms of cranial metastasis. 526 had parenchymal cerebral metastasis, and 21 only meningeal metastasis. Of these 526 patients found to have brain metastasis, 164 had single metastasis (31.2%), and 362 multiple (68.8%). Most of the cerebral metastatic lesions showed uniform or ring enhancement after intravenous injection of contrast medium, dura-arachnoid metastasis showed continuous and thick-curve enhancement at the cerebral convex, but not extending to the sulcus, while pia-dura metastasis displayed as thin and linear or nodular enhancement extending to the adjacent sulci.

CONCLUSION

The most common primary lesion with metastasis to the brain were lung cancers, followed by breast and gastrointestinal cancers. By using gadolinium-DTPA enhanced MR imaging, many single and small cerebral metastasis could be found earlier.

Behavioral and physiological features of chickens diversely selected for resistance to Avian Disease. 1. Selected inbred lines differ in behavioral and physical responses to social stress

To test the hypothesis that genetic variations in response to social stress modulate susceptibility to disease in poultry, aggressive behaviors induced by social stress were measured in chickens of different inbred lines selected for disease resistance (line 63) or susceptibility (lines 72 and 15I5), as well as 2 recombinant congenic strains (B and X). At 15 wk of age, roosters from each genetic line or strain were randomly assigned to pairs for intraline male-male aggression tests (n = 8 per line). Based on the results of the intraline aggression tests, the roosters were divided into 2 groups, winners and losers. At 16 wk of age, the roosters were randomly paired as winners vs. winners and losers vs. losers for interline aggression tests, i.e., line 63 vs. 72 and 15I5; line 73 vs. line 15I5; and strain X vs. strain B. Similarly, at 17 wk of age, line 63 vs. strains X and B, and line 72 vs. strains X and B were tested. The tests were conducted in a novel cage that was similar to their home cages, to provide a neutral space for both roosters being tested. Each pair was videotaped for 15 min. Male-male interaction-induced aggressive behaviors were markedly different among the genetic lines. Compared with roosters of lines 15I5 and 72, line 63 roosters generally showed fewer aggressive behaviors, including aggressive pecks and fights, as well as durations (P < 0.05). Roosters of the recombinant congenic strains X and B, each possessing a unique random 87.5% genome of line 63, exhibited low aggressive behaviors, which were similar or equal to the level of line 63 in both intraline and interline aggression tests (P = 0.05). These results may indicate that some of the gene(s) commonly carried between strains X and B as well as line 63 likely played an important role in governing their lower levels of aggression. The present chicken lines may be used as animal models for investigation of the cellular mechanisms of genetic-environmental interactions on disease resistance and stress responses.