Two new species of the mealybug genus Paracoccus from Jiangxi, South China (Hemiptera, Coccomorpha, Pseudococcidae).

Two new mealybug species, Paracoccusgillianwatsonae Zhang, sp. nov. and P.wui Zhang, sp. nov., collected from Jiangxi, South China, are described and illustrated based on the morphology of adult females. Paracoccusgillianwatsonae is similar to P.burnerae (Brain, 1915), but it differs in having fewer pairs of cerarii, and in lacking both ventral oral collar tubular ducts on the margins of the head and translucent pores on the hind femur. Paracoccuswui resembles P.keralae Williams, 2004 and P.neocarens (Lit, 1992), but it differs in lacking ventral oral collar tubular ducts on the margins of the head and in having multilocular disc-pores usually in double rows at the posterior edges of abdominal segments V and VI. A key to the Paracoccus species found in China is provided.

Factors Influencing Copulation Duration in Dastarcus helophoroides (Fairmaire) (Coleoptera: Bothrideridae).

The gregarious ectoparasitic beetle Dastarcus helophoroides (Fairmaire) is considered a primary biocontrol agent for controlling several cerambycid pests in East Asian countries. A thorough study of reproductive behavior is a prerequisite for the mass production of natural insect predators. Nonetheless, little attention has been given to this ectoparasitic beetle. We performed a series of trials to assess whether the adult copulation duration, a key behavioral trait, is differentially influenced by physiological and ecological factors, including body size, mating history, kinship, sex ratio, mating sequence, feeding status, ambient temperature, photoperiod, and time of day. Additionally, the effect of the copulation duration on the reproductive output of this beetle was also investigated. The results indicated that the copulation duration varied considerably, ranging from 1.12 min to 16.40 min and lasting for an average of 9.11 ± 0.12 min. Females with longer copulations laid more eggs and had a greater proportion of eggs hatched. Medium-sized individuals copulated significantly longer than small- and large-sized individuals. The copulation durations were significantly longer when both sexes experienced an asymmetric mating history than when both sexes experienced a symmetric mating history. Inbred couples copulated significantly longer than outbred couples. In terms of the adult sex ratio, increasing the density of females (polygamous group) or males (polyandrous group) led to significantly longer copulation durations than those in the monogamous group. The copulation durations gradually decreased with increasing the mating sequence and temperature. Food-absence couples copulated significantly longer than food-presence couples. The mean copulation duration of the scotophase was significantly longer than that of the photophase. These results demonstrate that all of the analyzed factors emerge as important factors influencing the copulation duration, ultimately affecting the reproductive outputs in this ectoparasitic beetle.

Regulatory roles of alternative splicing at Ezh2 gene in mouse oocytes.

BACKGROUND: Enhancer of zeste homologue 2 (EZH2), the core member of polycomb repressive complex 2 (PRC2), has multiple splicing modes and performs various physiological functions. However, function and mechanism of alternative splicing at Ezh2 exon 3 in reproduction are unknown. METHODS: We generated Ezh2Long and Ezh2Short mouse models with different point mutations at the Ezh2 exon 3 alternative splicing site, and each mutant mouse model expressed either the long or the short isoform of Ezh2. We examined mutant mouse fertility and oocyte development to assess the function of Ezh2 alternative splicing at exon 3 in the reproductive system. RESULTS: We found that Ezh2Long female mice had normal fertility. However, Ezh2Short female mice had significantly decreased fertility and obstructed oogenesis, with compromised mitochondrial function in Ezh2Short oocytes. Interestingly, increased EZH2 protein abundance and accumulated H3K27me3 were observed in Ezh2Short oocytes. CONCLUSIONS: Our results demonstrate that correct Ezh2 alternative splicing at exon 3 is important for mouse oogenesis.

A multi-year dormancy strategy in a cabbage beetle population in southeastern China.

The life cycle of the cabbage beetle Colaphellus bowringi in southeastern China is complex due to four options for adult development: summer diapause, winter diapause, prolonged diapsuse, and nondiapause. However, detailed information on the multi-year emergence patterns of diapausing individuals in this beetle has not been documented. In this study, we monitored the adult emergence patterns of diapausing individuals and estimated the influence of the diapause-inducing temperature and photoperiod on the incidence of prolonged diapause under seminatural conditions for several years. The duration of diapause for adults collected from the vegetable fields in different years varied from several months to 5 years. Approximately 25.9%-29.2% of individuals showed prolonged diapause (emergence more than 1 year after entering diapause) over the 5 years of observation. Furthermore, regardless of insect age, the emergence of diapausing adults from the soil always occurred between mid-February and March in spring and between late August and mid-October in autumn, when the host plants were available. The influence of diapause-inducing temperatures (22, 25, and 28°C) combined with different photoperiods (L:D 12:12 h and L:D 14:10 h) on diapause duration was tested under seminatural conditions. Pairwise comparisons of diapause duration performed by the log-rank test revealed that the low temperature of 22°C combined with the long photoperiod of L:D 14:10 h induced the longest diapause duration, whereas the low temperature of 22°C combined with the short photoperiod of L:D 12:12 h induced the highest proportion of prolonged diapause. This study indicates that C. bowringi adopts a multi-year dormancy strategy to survive local environmental conditions and unpredictable risks.

H3.3 kinetics predicts chromatin compaction status of parental genomes in early embryos.

BACKGROUND: After fertilization, the fusion of gametes results in the formation of totipotent zygote. During sperm-egg fusion, maternal factors participate in parental chromatin remodeling. H3.3 is a histone H3 variant that plays essential roles in mouse embryogenesis. METHODS: Here, we used transgenic early embryos expressing H3.3-eGFP or H2B-mCherry to elucidate changes of histone mobility. RESULTS: We used FRAP analysis to identify that maternally stored H3.3 has a more significant change than H2B during maternal-to-embryonic transition. We also found that H3.3 mobile fraction, which may be regulated by de novo H3.3 incorporation, reflects chromatin compaction of parental genomes in GV oocytes and early embryos. CONCLUSIONS: Our results show that H3.3 kinetics in GV oocytes and early embryos is highly correlated with chromatin compaction status of parental genomes, indicating critical roles of H3.3 in higher-order chromatin organization.

A new Atrococcus species (Hemiptera, Coccomorpha, Pseudococcidae) from China, with a key to Chinese species.

A new mealybug species Atrococcus rushuiensis Zhang, sp. nov., collected under the leaf sheath of Sporobolus fertilis (Poaceae) in Fuzhou City, Jiangxi Province, China, is described and illustrated. A new combination is introduced, transferring Allotrionymus shanxiensis Wu to the genus Atrococcus as A. shanxiensis (Wu), comb. nov. A key is presented for the species of Atrococcus recorded from China.

Comparison of sexual compatibility in crosses between the southern and northern populations of the cabbage beetle Colaphellus bowringi.

It is widely accepted that the genetic divergence and reproductive incompatibility between closely related species and/or populations is often viewed as an important step toward speciation. In this study, sexual compatibility in crosses between the southern XS population and the northern TA population of the polyandrous cabbage beetle Colaphellus bowringi was investigated by testing their mating preferences, mating latency, copulation duration, and reproductive performances of post-mating. In choice mating experiments, the percentages of matings were significantly higher in intra-population crosses than in inter-population crosses. Both isolation index (I) and index of pair sexual isolation (IPSI ) indicated partial mating incompatibility or assortative mating in crosses between the two different geographical populations. In single pair mating experiments, XS females in inter-population crosses mated significantly later and copulated significantly shorter than those in intra-population crosses. However, TA females in inter-population crosses mated significantly earlier and copulated longer than those in intra-population crosses, suggesting that larger XS males may enhance heterotypic mating. The lifetime fecundity was highest in XS homotypic matings, lowest in TA homotypic matings, and intermediate in heterotypic matings between their parents. The inter-population crosses resulted in significantly lower egg hatching rate and shorter female longevity than intra-population crosses. These results demonstrated that there exist some incompatibilities in premating, postmating-prezygotic, and postzygotic stages between the southern XS population and northern TA population of the cabbage beetle Colaphellus bowringi.

The influence of female age on male mating preference and reproductive success in cabbage beetle, Colaphellus bowringi.

The influence of female age on male mating preference and reproductive success has been studied using a promiscuous cabbage beetle, Colaphellus bowringi Baly (Coleoptera: Chrysomelidae). In a simultaneous choice test, middle-aged females had significantly greater mating success than young and old females. In single pair trials, when paired with middle-aged virgin males, middle-aged females mated faster, copulated longer, and had greater fecundity and fertility than young or old females, while the longevity of males was not significantly affected by female age. This study on C. bowringi suggests that middle-aged females are more receptive to mating, which can result in the highest male reproductive success.

[Impacts on repeated common cold for the adults with different constitutions treated by acupoint application in the dog days and the three nine-day periods after the winter solstice].

OBJECTIVE: To observe the impacts on repeated common cold for the adults with different constitutions treated by acupoint application in the dog days (the three periods of the hottest days) and the three nine-day periods after the winter solstice (the three periods of the coldest days). METHODS: One hundred and fifty-two cases of repeated common cold were divided into four zones according to the body constitution. Each zone was sub-divided into a group of the dog days + the three nine-day periods of the coldest days (group A), and a simple group of the dog periods (group B). In both groups, Dazhui (GV 14), Feishu (BL 13), Tiantu (CV 22), Danzhong (CV 17), Zhongfu (LU 1) and Shenshu (BL 23) were selected. In group A, the acupoint application was given on the 1st or 2nd day of the first, second and third periods of the hottest days in 2010, as well as the 1st or 2nd day of the first, second and third periods of the coldest days in 2010 separately. In group B, the acupoint application was only given on the 1st or 2nd day of the first, second and third periods of the hottest days in 2010. The follow-up visit was conducted before the acupoint application in the three periods of the coldest days in 2010 and before the acupoint application in the three periods of the hottest days in 2011. Additionally, the frequency of disease attack and the symptom score in sickness were taken as the observation indices for the efficacy assessment in both groups. RESULTS: (1) In both groups, the attack frequency was reduced obviously in half a year after the three periods of the hottest days for the patients of qi deficiency constitution, yang deficiency constitution and qi stagnation constitution and the clinical symptom score were reduced apparently (all P<0.01), which were superior to those for the patients of phlegm damp constitution (P<0.01, P<0.05). For the patients of phlegm damp constitution, only the clinical symptom score was reduced (P<0.01). (2) In group A, the improvements were received in the attack frequency and the clinical symptom score in half a year after the three periods of the coldest days for the patients of those four constitutions as compared with those before treatment (all P<0.01). In group B, the attack frequency and the clinical symptom score were all back to the level as those before treatment. (3) In group A, in half a year after the three periods of the coldest days, the efficacy for reducing the attack frequency and the improvements in the clinical symptoms were better than those in group B (all P<0.01). CONCLUSION: The acupoint application in the dog days and the three nine-day periods after the winter solstice reduces the attack frequency and relieves the clinical symptoms of common cold for the adults of individual constitutions to different extents. The efficacy can be further improved in the treatment with the acupoint application in the three nine-day periods after the winter solstice half a year after the acupoint application in the dog days.

Effects of N-n-butyl haloperidol iodide on the rat myocardial sarcoplasmic reticulum Ca(2+)-ATPase during ischemia/reperfusion.

We have previously shown that N-n-butyl haloperidol iodide (F(2)), a newly synthesized compound, reduces ischemia/reperfusion (I/R) injury by preventing intracellular Ca(2+) overload through inhibiting L-type calcium channels and outward current of Na(+)/Ca(2+) exchanger. This study was to investigate the effects of F(2) on activity and protein expression of the rat myocardial sarcoplasmic reticulum Ca(2+)-ATPase (SERCA) during I/R to discover other molecular mechanisms by which F(2) maintains intracellular Ca(2+) homeostasis. In an in vivo rat model of myocardial I/R achieved by occluding coronary artery for 30-60 min followed by 0-120 min reperfusion, treatment with F(2) (0.25, 0.5, 1, 2 and 4 mg/kg, respectively) dose-dependently inhibited the I/R-induced decrease in SERCA activity. However, neither different durations of I/R nor different doses of F(2) altered the expression levels of myocardial SERCA2a protein. These results indicate that F(2) exerts cardioprotective effects against I/R injury by inhibiting I/R-mediated decrease in SERCA activity by a mechanism independent of SERCA2a protein levels modulation.

[Observation of the therapeutic effect on COPD of cold phlegm blocking the lung type at stable stage treated with acupoint sticking therapy in different season].

OBJECTIVE: To systematically observe the clinical effect on chronic obstructive pulmonary disease (COPD) at the stable stage, differentiated as cold phlegm blocking the lung type, treated with acupoint sticking therapy during the dog days and the three nine-day periods after the winter solstice so as to propose the latest clinical idea and theoretic evidence for the treatment of COPD. METHODS: One hundred and fifty cases of COPD at stable stage, which were in accordance with the inclusive standard were randomly divided into three groups, named group A (treatment in dog days and the three nine-day periods after the winter solstice), group B (treatment in dog days) and group C (treatment in the three nine-day periods after the winter solstice), 50 cases in each group. The ingredients (Semen Brassicae, Euphoribia Kansui, Asarum, Rhizome Corydalis, Cinnamon, ginger juice) and doses of herbal medicine plaster were same in each group. The herbal plaster was applied to Feishu (BL 13), Shenshu (BL 23), Dazhui (GV 14), Tiantu (CV 22), Danzhong (CV 17) and Zhongfu (LU 1). In group B, the treatment was given once on the 1st day of each dog-day period, totally 3 treatments were included. In group C, the treatment was given once on the 1st day of each nine-day periods after the winter solstice, totally, 3 treatments were involved. In group A, the treatment was given once on the 1st day of each dog-day period and each nine-day periods after the winter solstice separately, totally 6 treatments were required. The therapeutic effect was evaluated in 4 aspects, named comprehensive clinical efficacy, survival quality (the scores for symptoms, activity limitation and influence on daily life), the attach frequency and pulmonary function. RESULTS: The total effective rate was 88.0% (46/50) in group A, which was superior to 76.0% (38/50) in group B and 70.0% (35/50) in group C separately (P < 0.01, P < 0.001). The results of the attack frequency, clinical symptom score and pulmonary function indices after treatment were all improved apparently as compared with those before treatment in each group (all P < 0.01). All the above indices in group A were improved much apparently as compared with the other two groups (P < 0.01, P < 0.001). Except for the level of forced vital capacity (FVC), the results of clinical symptom score and the other pulmonary function indices in group B were all improved significantly as compared with group C (P < 0.05, P < 0.001). CONCLUSION: Acupoint sticking therapy during different season of the year achieves a superior clinical efficacy for the patients with COPD at stable stage. This therapy can reduce the attack frequency and improve the survival quality and pulmonary function for the patients. It is concluded that the efficacy of the treatment in dog days and the three nine-day periods after the winter solstice is superior to simple dog-day treatment and the treatment in the three nine-day periods after the winter solstice, and the efficacy of dog days treatment is better than that in the three nine-day periods after the winter solstice.

Cardiac electrophysiological and antiarrhythmic effects of N-n-butyl haloperidol iodide.

AIMS: N-n-butyl haloperidol (F(2)), a novel compound of quaternary ammonium salt derivatives of haloperidol, was reported to antagonize myocardial ischemia/reperfusion injuries. The antiarrhythmic potential and electrophysiological effects of F(2) on rat cardiac tissues were investigated. METHODS AND RESULTS: In Langendorff-perfused rat hearts, the ventricular arrhythmias were induced by left anterior descending coronary artery of rat heart ligated for 20 min before the release of the ligature. F(2) provided some inhibitive effects against ischemia- and reperfusion-induced ventricular arrhythmias. In His bundle electrogram and epicardial ECG recordings, the drug produced bradycardia, delayed the conduction through the atrioventricular node and prolonged the Wenckebach cycle length and atrioventricular nodal effective refractory period. In whole-cell patch-clamp study, F(2) primarily inhibited the L-type Ca2+ current (I(Ca,L)) (IC(50) = 0.17 microM) with tonic blocking properties and little use-dependence. And the drug also decreased the Na+ current (IC(50) = 77.5 microM), the transient outward K+ current (IC(50) = 20.4 microM), the steady-state outward K+ current (IC(50) = 56.2 microM) and the inward rectifier K+ current (IC(50) = 127.3 microM). CONCLUSION: F(2) may be a promising drug for the treatment of ischemic heart disease with cardiac arrhythmia.

Photoperiodism of diapause induction in Thyrassia penangae (Lepidoptera: Zygaenidae).

Thyrassia penangae enters winter diapause as a prepupa in a cocoon. Photoperiodism of diapause induction was systematically investigated in this moth. The photoperiodic response curves under 24-h light-dark cycles showed that this insect is a typical long-day species. The critical daylength was 13h 30min at 25 degrees C, 13h at 30 degrees C and 12h 20min at 28 degrees C. Transferring experiments from a short day (LD 12:12) to a long day (LD 15:9) or vice versa indicated that photoperiodic sensitivity mainly occurs during the larval period. In experiments using non-24-h light-dark cycles, when the length of photophase exceeded the critical daylength (13.5h), was diapause inhibited effectively, even when the length of scotophase exceeded the critical nightlength (10.5h). Only when a long scotophase was combined with a short photophase, diapause was induced effectively. This result suggests that daylength measurement is more important than nightlength measurement in T. penangae. Night interruption experiments under 24-h light-dark cycles exhibited two points of apparent light sensitivity, but the photosensitive position was highly influenced by temperature and the length of scotophase. Nanda-Hamner experiments failed to reveal the involvement of a circadian system in this photoperiodic time measurement. All light-dark cycles from LD 12:12 to LD 12:72 resulted in a short day response, and all cycles from LD 14:4 to LD 14:72 resulted in a long day response, suggesting that photoperiodic time measurement in this moth is performed by a day-interval timer or an hourglass-like clock.

Reformative cannula electrodes for His bundle electrogram recording in isolated rat hearts.

His bundle electrogram (HBE) recording is an important method for the study of the atrioventricular conduction system. However, the current HBE recording methods in isolated animal hearts have some disadvantages, such as unstable recording due to the difficulty in fixing electrodes as a result of intense heart beat, the small amplitude of the His signal or the possibility to destroy the integrity of heart structure. To overcome these disadvantages, we designed and manufactured reliable, inexpensive and easy-made bipolar cannula electrodes, which combine the functions of Langendorff-perfusion aortic cannula and recording electrodes. With the cannula electrodes, the operation of HBE recording becomes easier and clearer; hence, more stable recordings can be obtained in isolated rat hearts.

Anti-cancer activity profile of 3'-azidothymidine 5'-[p-methoxyphenyl methoxyalaninyl phosphate] (Compound 003), a novel nucleoside analog.

The novel cytotoxic nucleoside analog Compound 003 (3'-azidothymidine 5'-[p-methoxyphenyl methoxyalaninyl phosphate], CAS 149560-32-7) prevented bipolar mitotic spindle assembly and caused a G2 arrest in human cancer cells. Compound 003 was very well tolerated by both mice and rats without any toxicity at cumulative dose levels >2 g/kg. Notably, Compound 003 prolonged cancer-free survival in the MMTVneu transgenic mouse model of HER2 positive breast cancer. These results indicate that Compound 003 may be useful in the treatment of cancer patients.

In vitro and in vivo pharmacokinetic features and metabolism of the novel cytotoxic nucleoside analog 3'-azidothymidine 5'-[p-methoxyphenyl methoxyalaninyl phosphate] (Compound 003).

The pharmacokinetic features and metabolism of the novel cytotoxic nucleoside analog Compound 003 (3'-azidothymidine 5'-[p-methoxyphenyl methoxyalaninyl phosphate], CAS 149560-32-7) were studied in both human cancer cells and mice. In mice, Compound 003 was rapidly converted into ala-AZT-MP (CAS 209214-06-2) and zidovudine (azidothymidine, AZT, CAS 30516-87-1). Maximum ala-AZT-MP concentrations were reached almost immediately (tmax < 5 min), while 50.4 min and 143.5 min were required to reach maximum AZT concentrations after intravenous and oral administration, respectively. The results indicate that paraoxon-sensitive carboxylesterases play an important role in the conversion of Compound 003 to ala-AZT-MP. This study provides the basis for future preclinical as well as clinical pharmacodynamic studies of Compound 003.

Phenylarsonic acid compounds with broad-spectrum and potent cytotoxic activity against human cancer cells.

The in vitro cytotoxic activity profile of nine novel phenylarsonic acid (CAS 98-05-5, PAA) compounds against 17 human cancer cell lines including (a) ovarian cancer cell lines ES-2, PA-1, CAOV-3, OVCAR-3, (b) testicular cancer cell lines Ntera-2, Tera-2, N2NICP, 833K, and 64CP, (c) multiple myeloma cell lines ARH77, HS-Sultan, RPMI-8226, and U266, and (d) acute lymphoblastic leukemia (ALL) cell lines NALM-6, MOLT-3, ALL-1, and RS4; 11, was determined by the MTT assay. The lead compounds, 2-methylthio-4-[(4'-aminophenylazo)-phenylarsonic acid] pyrimidine (PHI-370) and 2-methylthio-4-(4'-phenylarsonic acid)-aminopyrimidine (PHI-380) caused apoptotic death in all 17 cancer cell lines at low micromolar concentrations, as documented by TUNEL assays and confocal laser scanning microscopy. PHI-380 was also tested and found to be very active against primary tumor cells isolated from surgical biopsy specimens of 14 patients with therapy-refractory non-small cell lung cancer, breast cancer, colon cancer, lymphoma, hepatoblastoma, or Wilm's tumor as well. Because of their broad-spectrum and potent anticancer activity and ability to induce apoptosis in primary tumor cells from therapy-refractory cancer patients, PAA compounds such as PHI-370 and PHI-380 may provide the basis for effective salvage regimens for patients with recurrent cancer.

Targeting JAK3 with JANEX-1 for prevention of autoimmune type 1 diabetes in NOD mice.

Here we show that Janus kinase (JAK) 3 is an important molecular target for treatment of autoimmune insulin-dependent (type 1) diabetes mellitus. The rationally designed JAK3 inhibitor JANEX-1 exhibited potent immunomodulatory activity and delayed the onset of diabetes in the NOD mouse model of autoimmune type 1 diabetes. Whereas 60% of vehicle-treated control NOD mice became diabetic by 25 weeks, the incidence of diabetes at 25 weeks was only 9% for NOD females treated with daily injections of JANEX-1 (100 mg/kg/day) from Week 10 through Week 25 (P = 0.007). Furthermore, JANEX-1 prevented the development of insulitis and diabetes in NOD-scid/scid females after adoptive transfer of splenocytes from diabetic NOD females. Chemical inhibitors such as JANEX-1 may provide the basis for effective treatment modalities against human type 1 diabetes. To our knowledge, this is the first report of the immunosuppressive activity of a JAK3 inhibitor in the context of an autoimmune disease.

Organic phenyl arsonic acid compounds with potent antileukemic activity.

A series of 12 organic arsonic acid compounds has been synthesized and evaluated against human B-lineage (NALM-6) and T-lineage (MOLT-3) acute lymphoblastic leukemia (ALL) cell lines. The lead compounds 2-trichloromethyl-4-[4'-(4"-phenylazo)phenylarsonic acid]aminoquinazoline (compound 19, PHI-P518; IC(50)=1.1+/-0.5 microM against NALM-6 and 2.0+/-0.8 microM against MOLT-3) and 2-methylthio-4-(2'-phenylarsonic acid)aminopyrimidine (compound 15, PHI-P381; IC(50)=1.5+/-0.3 microM against NALM-6 and 2.3+/-0.5 microM against MOLT-3) exhibited potent antileukemic activity at low micromolar concentrations.

Treatment of post-bone marrow transplant acute graft-versus-host disease with a rationally designed JAK3 inhibitor.

Here we show that the Janus kinase 3 (JAK3) inhibitor 4-(3'-hydroxyphenyl)-amino-6,7-dimethoxyquinazoline (JANEX-3) exhibits potent anti-GVHD activity and consequently improves the post-BMT survival outcome of C57BL/6 (H-2b) recipient mice transplanted with allogeneic bone marrow/splenocyte (BM/S) grafts from MHC disparate BALB/c mice (H-2d). One hundred percent of the vehicle-treated allograft recipients developed severe GVHD and died with a median survival of 41 days. Treatment of recipient mice with JANEX-3 (30 mg/kg/day, 3 x/day) after the onset of rapidly progressive severe GVHD in the 3rd week after BMT significantly improved the survival of BMT recipients with GVHD and prolonged the median survival time to 78 days (P < 0.0001, log-rank test). The probability of survival at two and three months post-BMT was 6 +/- 6% and 0 +/- 0% for vehicle-treated control mice and 100 +/- 0% and 38 +/- 17% for mice treated with JANEX-3. These results prompted the hypothesis that JAK3 plays a pivotal role in the pathophysiology of GVHD. To test this hypothesis, we examined if mice transplanted with allogeneic BM/S grafts from Jak3 knockout mice Jak3-/- develop GVHD. The allografts from (Jak3-/-) C57BL/6 (H-2b) mice rescued MHC-disparate recipient BALB/c mice (H-2d) of the lethal toxicity of TBI without causing fatal GVHD. Taken together, these observations establish JAK3 as a key mediator of severe GVHD after allogeneic BMT in the context of a major-HLA disparity.