The genomic history and global migration of a windborne pest

Many insect pests, including the brown planthopper (BPH), undergo windborne migration that is challenging to observe and track. It remains controversial about their migration patterns and largely unknown regarding the underlying genetic basis. By analyzing 360 whole genomes from around the globe, we clarify the genetic sources of worldwide BPHs and illuminate a landscape of BPH migration showing that East Asian populations perform closed-circuit journeys between Indochina and the Far East, while populations of Malay Archipelago and South Asia undergo one-way migration to Indochina. We further find round-trip migration accelerates population differentiation, with highly diverged regions enriching in a gene desert chromosome that is simultaneously the speciation hotspot between BPH and related species. This study not only shows the power of applying genomic approaches to demystify the migration in windborne migrants but also enhances our understanding of how seasonal movements affect speciation and evolution in insects.

Molecular and biological characterization of a bunyavirus infecting the brown planthopper (Nilaparvata lugens)

A negative-strand symbiotic RNA virus, tentatively named Nilaparvata lugens Bunyavirus (NLBV), was identified in the brown planthopper (BPH, Nilaparvata lugens). Phylogenetic analysis indicated that NLBV is a member of the genus Mobuvirus (family Phenuiviridae, order Bunyavirales). Analysis of virus-derived small interfering RNA suggested that antiviral immunity of BPH was successfully activated by NLBV infection. Tissue-specific investigation showed that NLBV was mainly accumulated in the fat-body of BPH adults. Moreover, NLBV was detected in eggs of viruliferous female BPHs, suggesting the possibility of vertical transmission of NLBV in BPH. Additionally, no significant differences were observed for the biological properties between NLBV-infected and NLBV-free BPHs. Finally, analysis of geographic distribution indicated that NLBV may be prevalent in Southeast Asia. This study provided a comprehensive characterization on the molecular and biological properties of a symbiotic virus in BPH, which will contribute to our understanding of the increasingly discovered RNA viruses in insects.

[Eculizumab in patients with paroxysmal nocturnal hemoglobinuria: a real-world study in China]

Objective: To evaluate the efficacy and safety of eculizumab in the treatment of paroxysmal nocturnal hemoglobinuria (PNH) in China. Methods: Data from PNH patients who received at least 3 months of full-dose eculizumab and were followed for at least 3 months between December 2022 and July 2023 were retrospectively collected. We evaluated changes in clinical and laboratory parameters after 1, 2, 3, and 6 months of eculizumab treatment. The rates of breakthrough hemolysis (BTH), extravascular hemolysis (EVH), and the occurrence of adverse reactions were also monitored. Results: The study included nine patients, six males and three females, with a median age of 54 (28-69) years. 5 of the patients had classic PNH, while 4 had PNH/AA. The number of episodes of hemoglobinuria was 5 (1-25) per month before eculizumab. 4 patients required blood transfusion, 5 had thrombosis and one had renal impairment before eculizumab. The median time to eculizumab was 6 (3-7) months and the followup period was 3 (3-6) months after treatment. The number of episodes of hemoglobinuria following eculizumab was 0 (0-1). During the followup period, no additional thrombotic events occurred. LDH at any time after eculizumab was lower than at baseline, and some patients' HGB increased. All transfused patients became transfusion-independent after receiving eculizumab. The FACIT-Fatigue score improved by an average of 17.3 points following treatment. 2 patients developed BTH and improved with symptomatic treatment. There were three adverse events that caused mild symptoms. There are no serious adverse events or deaths. Conclusion: Eculizumab can effectively control the hemolytic-related symptoms of PNH in China, reducing the need for blood transfusions to some extent, while also demonstrating a higher safety profile.

Co-option of a non-retroviral endogenous viral element in planthoppers

Non-retroviral endogenous viral elements (nrEVEs) are widely dispersed throughout the genomes of eukaryotes. Although nrEVEs are known to be involved in host antiviral immunity, it remains an open question whether they can be domesticated as functional proteins to serve cellular innovations in arthropods. In this study, we found that endogenous toti-like viral elements (ToEVEs) are ubiquitously integrated into the genomes of three planthopper species, with highly variable distributions and polymorphism levels in planthopper populations. Three ToEVEs display exon‒intron structures and active transcription, suggesting that they might have been domesticated by planthoppers. CRISPR/Cas9 experiments revealed that one ToEVE in Nilaparvata lugens, NlToEVE14, has been co-opted by its host and plays essential roles in planthopper development and fecundity. Large-scale analysis of ToEVEs in arthropod genomes indicated that the number of arthropod nrEVEs is currently underestimated and that they may contribute to the functional diversity of arthropod genes.

A chromosome-level genome assembly of Stenchaetothrips biformis and comparative genomic analysis highlights distinct host adaptations among thrips

Insects have a limited host range due to genomic adaptation. Thysanoptera, commonly known as thrips, occupies distinct feeding habitats, but there is a lack of comparative genomic analyses and limited genomic resources available. In this study, the chromosome-level genome of Stenchaetothrips biformis, an oligophagous pest of rice, is assembled using multiple sequencing technologies, including PacBio, Illumina short-reads, and Hi-C technology. A 338.86 Mb genome is obtained, consisting of 1269 contigs with a contig N50 size of 381 kb and a scaffold N50 size of 18.21 Mb. Thereafter, 17,167 protein-coding genes and 36.25% repetitive elements are annotated. Comparative genomic analyses with two other polyphagous thrips, revealing contracted chemosensory-related and expanded stress response and detoxification gene families in S. biformis, potentially facilitating rice adaptation. In the polyphagous thrips species Frankliniella occidentalis and Thrips palmi, expanded gene families are enriched in metabolism of aromatic and anthocyanin-containing compounds, immunity against viruses, and detoxification enzymes. These expansion gene families play crucial roles not only in adapting to hosts but also in development of pesticide resistance, as evidenced by transcriptome results after insecticides treatment. This study provides a chromosome-level genome assembly and lays the foundation for further studies on thrips evolution and pest management.

High-throughput sequencing yields a complete mitochondrial genome of the rice thrips, Stenchaetothrips biformis (Thysanoptera: Thripidae)

Rice thrips, Stenchaetothrips biformis (Bagnall, 1913), are one of the destructive pests of rice. Here, the complete mitochondrial genome of S. biformis was sequenced using high-throughput sequencing. The mitogenome is 15,359 bp long with an A + T content of 76.94%, which contains 13 protein-coding genes (PCGs), 22 transfer RNA (tRNAs), 2 ribosomal RNA genes (rRNAs) and 2 putative control regions (CRs). The phylogenetic analysis showed that S. biformis is closely related to Thrips imaginis and Thrips palmi. This new mitochondrial genome data can be better used to provide a basis for studies of the mitochondrial evolution of Thysanoptera.

[Effects of vaccines on the viral negative conversion of children with COVID-19]

Objective: To explore the effect of vaccination on viral negative conversion of children with COVID-19. Methods: A retrospective cohort study was conducted. A cohort of 189 children aged 3-14 years with COVID-19 admitted to Renji Hospital (South branch) of Shanghai Jiao Tong University School of Medicine from April 7^th to May 19^th 2022 was enrolled in the study. According to the vaccination status, the infected children were divided into an unvaccinated group and a vaccinated group. Age, gender, severity, clinical manifestations, and laboratory tests, etc. were compared between groups, by rank sum test or chi-square test. The effects of vaccination on viral negative conversion were analyzed by a Cox mixed-effects regression model. Additionally, a questionnaire survey was conducted among the parents of unvaccinated children to analyze the reasons for not being vaccinated. Results: A total of 189 children aged 3-14 years were enrolled, including 95 males (50.3%) and 94 females (49.7%), aged 5.7 (4.1,8.6) years. There were 117 cases (61.9%) in the unvaccinated group and 72 cases (38.1%) in the vaccinated group. The age of the vaccinated group was higher than that of the unvaccinated group (8.8 (6.8, 10.6) vs. 4.5 (3.6, 5.9) years, Z=9.45, P<0.001). No significant differences were found in clinical manifestations, disease severity, and laboratory results between groups (all P>0.05), except for the occurrence rate of cough symptoms, which was significantly higher in the vaccinated group than in the non-vaccinated group (68.1% (49/72) vs. 50.4% (59/117),χ²=5.67, P=0.017). The Kaplan-Meier survival curve and Cox mixed-effects regression model showed that the time to the viral negative conversion was significantly shorter in the vaccinated group compared with the unvaccinated group (8 (7, 10) vs. 11 (9, 12) d, Z=5.20, P<0.001; adjusted HR=2.19 (95%CI 1.62-2.97)). For questionnaire survey on the reasons for not receiving a vaccination, 115 questionnaires were distributed and 112 valid questionnaires (97.4%) were collected. The main reasons for not being vaccinated were that parents thought that their children were not in the range of appropriate age for vaccination (51 cases, 45.5%) and children were in special physical conditions (47 cases, 42.0%). Conclusion: Vaccination can effectively shorten the negative conversion time of children with COVID-19 and targeted programs should be developed to increase eligible children's vaccination rate for SARS-CoV-2 vaccination.

Chromosome-level Assembly, Dosage Compensation and Sex-biased Gene Expression in the Small Brown Planthopper, Laodelphax striatellus

In insects, sex chromosome differentiation often results in unequal gene dosages between sexes. Dosage compensation mechanisms evolve to balance gene expression, but the degree and mechanism of regulation often vary by insect species. In hemipteran species, the small brown planthopper (SBPH), Laodelphax striatellus, is an injurious crop pest, with a sex chromosome type XX in females and XO in males. This species offers the opportunity to study dosage compensation and sex-biased gene expression. In this study, we generated a chromosome-level genome of SBPH using Oxford Nanopore Technologies and high-throughput chromatin conformation capture (Hi-C) technology. We also sequenced RNA-seq data from 16 tissue samples to annotate the genome and analyze gene dosage compensation. We finally obtained a 510.2 megabases (Mb) genome with 99.12% of the scaffolds anchored on 15 chromosomes (14 autosomes and 1 X chromosome) and annotated 16,160 protein-coding genes based on full-length cDNA sequencing data. Furthermore, we found complete dosage compensation in all L. striatellus somatic tissues, but lack of dosage compensation in gonad tissue testis. We also found that female-biased genes were significantly enriched on the X chromosome in all tissues, whereas male-biased genes in gonad tissues were enriched on autosomes. This study not only provides a high-quality genome assembly but also lays a foundation for a better understanding of the sexual regulatory network in hemipteran insects.

A feminizing switch in a hemimetabolous insect

The mechanism of sex determination remains poorly understood in hemimetabolous insects. Here, in the brown planthopper (BPH), Nilaparvata lugens, a hemipteran rice pest, we identified a feminizing switch or a female determiner (Nlfmd) that encodes a serine/arginine-rich protein. Knockdown of Nlfmd in female nymphs resulted in masculinization of both the somatic morphology and doublesex splicing. The female-specific isoform of Nlfmd, Nlfmd-F, is maternally deposited and zygotically transcribed. Depletion of Nlfmd by maternal RNAi or CRISPR-Cas9 resulted in female-specific embryonic lethality. Knockdown of an hnRNP40 family gene named female determiner 2 (Nlfmd2) also conferred masculinization. In vitro experiments showed that an Nlfmd2 isoform, NlFMD2³⁴⁰, bound the RAAGAA repeat motif in the Nldsx pre-mRNA and formed a protein complex with NlFMD-F to modulate Nldsx splicing, suggesting that NlFMD2 may function as an RNA binding partner of the feminizing switch NlFMD. Our results provide novel insights into the diverse mechanisms of insect sex determination.

Chromosome-level assembly of the brown planthopper genome with a characterized Y chromosome

Hundreds of insect genome sequences have been reported; however, most sequencing projects have not determined the sex chromosomes, and no Y chromosomes from a heterometabolous insect have been identified and characterized to date. The brown planthopper (Nilaparvata lugens Stål) is the most economically damaging pest to rice and is also an ideal research subject for paddy ecology and functional genomics. We previously assembled a draft female genome mainly using second-generation sequencing technologies, with a contig N50 of only 24 kb, due to the large size and excessive repetitive regions in the N. lugens genome. Here, we utilize third-generation sequencing technologies and Hi-C data to generate a high-quality male N. lugens assembly with a contig N50 of 1.01 Mb, a scaffold N50 of 69.96 Mb and more than 95.6% of the assembled bases located on 16 chromosomes. Fourteen autosomes and two sex chromosomes (X + Y) were identified, filling in the gap related to the Y chromosome in heterometabolous insects. A total of 18,021 protein-coding genes and 6423 long-noncoding RNAs were predicted with full-length cDNA sequencing data. All 315 of the Y chromosome genes (Y-genes) were derived from autosomal and X-chromosome duplications. Large-scale RNA interference (RNAi) experiments were conducted against the N. lugens Y-genes, demonstrating that 7 Y-genes were essential for normal BPH development or male organ development, suggesting the importance of Y-genes. The first identified Y chromosome in heterometabolous insects will help gain more insight into sex determination, fertility and chromosome evolution.

Identification and functional analysis of the doublesex gene in the sexual development of a hemimetabolous insect, the brown planthopper

In the sex determination cascade, the genes dsx (doublesex) in insects, mab-3 (male abnormal 3) in nematodes, and Dmrt1 (dsx/mab-3 related transcription factor-1) in vertebrates act as the base molecular switches and play important roles. Moreover, these genes share the same conserved feature domain-DNA-binding oligomerization domain (OD1), and female-specific dsx also has a conserved oligomerization domain 2 (OD2). Although sex determination and the functions of dsx in several holometabolous insects have been well documented, sex determination and the function of dsx in hemimetabolous insects remain a mystery. In this study, four dsx homologs were unexpectedly found in the Nilaparvata lugens (brown planthopper, BPH, order Hemiptera), which also showed a different evolutionary status. We found that only one of the four homologs, Nldsx, which has three alternative splicing variants (female-specific Nldsx^F, male-specific Nldsx^M, non-sex-specific Nldsx^C), was required in the sexual development of N. lugens. Compared with that of holometabolous species, the dsx of N. lugens contains a less conserved OD1, while the OD2 domain of BPH was not identifiable because the common region is poorly conserved, and the female-specific region is short. RNAi-mediated knockdown of Nldsx in female BPH resulted in a larger body size with a normal abdomen and reproductive system, while no changes in fertility were noted. However, adult males with RNA interference knockdown of Nldsx^M in nymphs became pseudofemales, were infertile, had abnormal copulatory organs, and had impassable deferent ducts with hyperplastic walls; additionally, the pseudofemales could not produce the normal courtship signals. Our results suggest that dsx plays a critical role in male BPH somatic development and mating behavior. This is the first study to show that dsx is essential for sexual development in a hemipteran species.

Differences on the biological function of three Ig isotypes in zebrafish: a gene expression profile

LPS challenge experiment was conducted to compare the different biological function of three Ig isotypes by checking the expression of Ig heavy chain in zebrafish adult and larvae. Overall, IgM and IgZ expression exceeded IgD in both the larvae and adult, and IgM expression exceeded IgZ in the larvae at later development stages and adult. Moreover, LPS challenge induced significant up-regulation of all the three Ig isotypes in adult zebrafish, and the increase range of IgM and IgZ significantly exceeded that of IgD, indicating that the former two Ig isotypes played more important immunological role in response to antigen invasion. In additon, LPS challenge induced marked responses of all the Ig isotypes in the larvae since 21 dpf onwards. The response pattern of three Ig isotypes after LPS challenge was very similar in the larvae on 21 dpf, but the response range of IgZ exceeded IgM and IgD, and IgZ responded to LPS challenge a bit faster than the other Ig isotypes in the larvae on 28 dpf, which might be related to its important role in the mucosal immunity that was firstly induced by LPS immersion.

Cationic microRNA-delivering nanovectors with bifunctional peptides for efficient treatment of PANC-1 xenograft model

Therapeutic strategies based on modulation of microRNA activity possess much promise in cancer therapy, but the in vivo delivery of microRNA to target sites and its penetration into tumor tissues remain great challenge. In this work, miR-34a-delivering therapeutic nanocomplexes with a tumor-targeting and -penetrating bifunctional CC9 peptide were proposed for efficient treatment of pancreatic cancers. In vitro study indicated that the nanoparticle-based miR-34a delivery systems could effectively facilitate cellular uptake and greatly up-regulate the mRNA level of miR-34a in PANC-1 cell lines. The up-regulation of miR-34a remarkably induced cell cycle arrest and apoptosis, suppressed the tumor cell migration and inhibited the target gene expressions such as E2F3, Bcl-2, c-myc and cyclin D1. More importantly, the in vivo systemic administration of the developed targeting miR-34a delivery systems in a pancreatic cancer model significantly inhibited tumor growth and induced cancer cell apoptosis. Such bifunctional peptide-conjugated miRNA-delivering nanocomplexes should have great potential applications in cancer therapy.

A gene nanocomplex conjugated with monoclonal antibodies for targeted therapy of hepatocellular carcinoma

To enhance tumor-targeting abilities and therapeutic efficiency, a monoclonal antibody-conjugated gene nanocomplex was herein designed. The biodegradable cationic polyethylenimine-grafted-α,β-poly(N-3-hydroxypropyl)-DL-aspartamide (PHPA-PEI) was used for complexing pDNA to form the PHPA-PEI/pDNA nanoparticle, and then 9B9 mAb, an anti-epidermal growth factor receptor (anti-EGFR) monoclonal antibody, was conjugated to produce the PHPA-PEI/pDNA/9B9 mAb (PP9mN) complex. The PP9mN complex with the diameter of around 300 nm at its optimal weight ratio could be uptaken effectively by SMMC-7721 cells. The cytotoxicity of the PP9mN complex was much lower than that of PEI 25 kD in SMMC-7721, HepG2, Bel-7404 and COS-7 cell lines. The PP9mN complex possessed the highly efficient in vitro gene delivery ability to the hepatocellular carcinoma cells. The in vivo gene expression indicated that PP9mN could target to the tumor tissues effectively. By using the therapeutic AChE gene, it was found that the PP9mN complexes significantly enhanced the anti-tumor effect on tumor-bearing nude mice. Such monoclonal antibody-conjugated gene complex should have great potential applications in liver cancer therapy.

Detection and identification of avian, duck, and goose reoviruses by RT-PCR: goose and duck reoviruses are part of the same genogroup in the genus Orthoreovirus

A reverse transcription-polymerase chain reaction (RT-PCR) procedure for the detection of avian, duck, and goose reovirus (ARV, DRV, and GRV) RNA from cell culture supernatant and clinical samples was established. Based on multiple sequence alignment, a pair of degenerate primers was selected and synthesized. The amplified, cloned, and sequenced 598-base-pair products from the sigmaA-encoding gene fragment from 16 isolates (ranging over 30 years) indicated that the primer regions were well conserved. The sensitivity of this method was determined to be 10(-2) PFU. The specificity of the RT-PCR method was determined by testing specimens containing avian influenza A viruses, Newcastle disease virus, and infectious bronchitis virus, all of which yielded negative results with no discernible background. The efficiency of the system for detection of ARV, DRV, and GRV directly in 71/83 clinical samples was confirmed. The nucleotide sequence analysis indicated that DRV and GRV isolated from China in different locales and years were closely related, showing 97.4-100% homology to each other, but with only 86.7-88.5% identity to DRV 89026. The nucleotide and amino acid sequence identities in the amplified sigmaA-encoding gene were 74.2-78.4% and 86.9-92.0%, respectively, between duck/goose and chicken species. Phylogenetic analysis indicated that GRV and DRV aggregated into the same specified genogroup within subgroup II of the genus Orthoreovirus and are more closely related to ARV than to Nelson Bay virus. Overall, this study developed a sensitive and specific technique for the identification ARV, DRV, and GRV, and sequencing analysis has enhanced our understanding of the evolutionary relationship between ARV, DRV, and GRV.

In vitro hematopoietic and endothelial potential of flk-1(-/-) embryonic stem cells and embryos

Mice deficient in the Flk-1 receptor tyrosine kinase are known to die in utero because of defective vascular and hematopoietic development. Here, we show that flk-1(-/-) embryonic stem cells are nevertheless able to differentiate into hematopoietic and endothelial cells in vitro, although they give rise to a greatly reduced number of blast colonies, a measure of hemangioblast potential. Furthermore, normal numbers of hematopoietic progenitors are found in 7.5-day postcoitum flk-1(-/-) embryos, even though 8. 5-day postcoitum flk-1(-/-) embryos are known to be deficient in such cells. Our results suggest that hematopoietic/endothelial progenitors arise independently of Flk-1, but that their subsequent migration and expansion require a Flk-1-mediated signal.

Immunogenicity and relative attenuation of different vaccinia-rabies virus recombinants

Immunogenicity and relative attenuation were examined for the following Tian Tan strain vaccinia-rabies recombinant viruses: 1) NGc-1, which coexpresses the glycoprotein (G) and nucleocapsid protein (N) of the rabies virus Challenge Virus Standard (CVS) strain; 2) Nc-1, which expresses the CVS N; 3) Gc-2, Gc-3, Gc-4, and Gc-5, which express CVS G via promoters from different vaccinia strains or from different vaccinia genome loci; 4) Ga-1, which expresses the G of rabies virus strain aG; and 5) Gas-1; which expresses the carboxyltruncated G ectodomain (Gs) of strain aG. All but Nc-1 and Gas-1 induced rabies virus neutralizing antibodies (VNAs) and protected groups of mice at very high frequencies from intramuscular (IM) or intracranial (IC) challenge with CVS or SW1 Shanghai dog street rabies virus (SRV); Nc-1 and Gas-1 were partly protective, more frequently against IM challenge. NGc-1 and Gc-5 appeared to induce high levels of VNAs sooner after immunization than the other constructs in mice. Relative attenuation assessed by IM infection of neonatal mice, IC infection of adult mice, and intradermal infection of rabbits with varying doses was best for NGc-1. All the recombinants were at least 100-fold more attenuated than the parent, Tian Tan vaccinia virus. Gc-2, Gc-3, Gc-4, Gc-5, and NGc-1 induced VNAs after immunization of dogs, and a subset of VNA-positive animals vaccinated with NGc-1 or Gc-3 were protected against an otherwise lethal IM injection of SRV at 21 days after vaccination.

Molecular characterization of a chromosome translocation breakpoint t(11;14)(p13;q11) from the cell line KOPT-K1

Recurrent chromosome translocations involving 11p13 and 14q11 are found in 5-10% of cases of T-ALL. The gene involved in the translocation on chromosome 14 is the T cell antigen receptor alpha or delta. The putative oncogene on chromosome 11 is rhombotin 2 (RBTN2)/translocated in T cell gene 2 (ttg-2), a member of the LIM family of proteins. In this paper we characterize a cell line KOPT-K1 that has a t(11;14)(p13;q11). The breakpoint on chromosome 11 involves an Alu-rich region with the break occurring between two Alu sequences on chromosome 11. In addition, approximately 70 bases from the break on chromosome 11 is a tetranucleotide repeat. Whether either of these structures played a role in the translocation is not known. No heptamer or nonamer sequences, implicated in other rearrangements were found near the breakpoint. The breakpoint on chromosome 11 maps more centromeric than previous translocations of this region. Despite this the RBTN2 gene is highly expressed in KOPT-K1. This cell line will be useful for investigating the role of RBTN2 in leukemogenesis and the mechanism by which the translocation alters the expression of RBTN2.

Influences of Polyactin A on activities of human monocytes in vitro

Effects of Polyactin A (PAA) on abilities of human monocytes to synthesize and secrete interleukin-1 (IL-1) and to modulate natural killer (NK) cell activity in large granular lymphocytes (LGL) were investigated in vitro. Over a wide range of concentrations (0.01-100 micrograms.ml-1), PAA directly induced IL-1 synthesis and secretion, showing the maximal effect at 10 micrograms.ml-1, and evidently synergized with lipopolysaccharides (LPS) of E coli in stimulation of IL-1 production by human monocytes. The manifestation of PAA pretreated autologous monocytes in modulation of NK cell activity was closely related to PAA concentration. A boosting effect of PAA-treated monocytes on NK activity was observed when PAA 10-100 micrograms.ml-1 were used for pretreatment of monocytes, while an inhibitory influence of monocytes was found when PAA 0.01-0.1 microgram.ml-1 were used. These results demonstrate significant effects of PAA on functions of human monocytes, enhancing IL-1 production and affecting their regulative activity on NK cell cytotoxicity.

Influences of a novel immunopotentiator polyactin A on interleukin 1 production and responsiveness in mice

Effects of a novel immunopotentiator Polyactin A (PAA), developed in China, on production and responsiveness of murine interleukin 1(IL-1) were investigated. The results demonstrated that: (1) PAA 0.01-100 micrograms.ml-1 directly induced IL-1 synthesis and secretion from murine peritoneal macrophages (PMO) and markedly enhanced IL-1 production of the mouse PMO stimulated by lipopolysaccharides (LPS) of E coli; (2) IL-1 release from the PMO cultured in PAA 0.1 micrograms.ml-1 was detectable as early as 2 h after the incubation, peaked at 24 h, and then decreased gradually; (3) PAA stimulated and enhanced both IL-1 synthesis and release, but its effect on IL-1 release was stronger; (4) PMO from the mice given po PAA 200 mg.kg-1.d-1 for 7 d produced a higher level of IL-1 than those from control group, and the increase in extracellular IL-1 was more significant than that in intracellular one; (5) in vivo, PAA had no effect on IL-1 receptor expression and IL-1 responsiveness of murine lymphocytes, but eliminated the suppressing effects of cyclophosphamide (Cyc) on IL-1 receptor expression and IL-1 responsiveness of mouse lymphocytes. The above findings provide new explanation for action of PAA and new basis for wider clinical applications of PAA.