granulocyte-macrophage - colony-stimulating factor

The use of cryoablation for colorectal liver metastases (CLM) remains limited and controversial. This study aimed to investigate the antitumor immune response following cryoablation combined with granulocyte-macrophage colony-stimulating factor (GM-CSF) treatment in a CLM mouse model.

A CLM mouse model was established using BALB/c mice. The tumor-bearing mice were randomly divided into Control group, GM-CSF group, cryoablation group, and cryoablation + GM-CSF group. Tumor size, survival time, dendritic cells (DCs) count, serum cytokine levels (IL-4, IFN-γ), and the Th1/Th2 ratio (IFN-γ/IL-4) were compared among the four groups.

The combination of cryoablation and GM-CSF demonstrated synergistic effects, resulting in the smallest tumor lesion, longest mean survival time, and highest DC count on day 21 post-treatment compared to other groups. Both cryoablation alone and combined with GM-CSF significantly increased serum IFN-γ levels and suppressed IL-4 levels on day 21 compared to pre-treatment levels (P<0.05). Notably, the combination of cryoablation and GM-CSF significantly elevated the Th1/Th2 ratio (P<0.05).

Combining cryoablation with GM-CSF treatment holds promise for CLM management. It exhibits increased DC infiltration within the tumor microenvironment, enhanced immune responses, and prolonged survival in tumor-bearing mice.

Pseudomonas aeruginosa, as an opportunistic pathogen, is known to cause nosocomial infections among patients suffering from burn injuries and also cystic fibrosis patients. The objective of our research was to develop a novel vaccine against P. aeruginosa. 

A recombinant P. aeruginosa subunit vaccine based on the outer membrane proteins, including the OprF-OprI region and its major protein in the type III secretion system, PopB (called FIB protein) was formulated. To induce a robust immune response, our preferred regions were conjugated to a carrier protein, GMCSF (Granulocyte-macrophage colony-stimulating factor). FIB protein’s immunogenicity with and without adjuvant was evaluated in vaccinated rats and also burned rat models, which were subcutaneously challenged by the PAO1 strain of P. aeruginosa.

Antibody levels were increased in sera of rats in this study. Assessment of the resident memory CD4+ T cells in splenocytes from vaccinated rats demonstrated that the FIB conjugated with GMCSF could cause higher responses in comparison with other groups. Moreover, immunization with the FIB plus adjuvant protein could improve interferon-gamma (IFN-γ) production, interleukin 17A (IL-17A), and IL-4, contributing to elicit humoral and cellular immune responses and decreased post-infection bacterial loads after PA challenge, pathology, and inflammatory cell infiltration. 

These observations demonstrated that FIB conjugated with GMCSF can be a putative vaccine candidate against P. aeruginosa in burnt rat models.

A novel strategy to increase protein expression yield is unintended induction of expression in complex media, called auto-induction. This method can be used to express proteins under control of the lac promoter without any need to monitor bacterial growth pattern, and addition of specific expression inducers such as Isopropyl β-D-1-thiogalactopyranoside (IPTG) at proper time. In the present study, a codon optimized gene encoding granulocyte-macrophage colony stimulating factor (GM-CSF) was cloned and over-expressed in Escherichia coli BL21 (DE3) using both conventional inducer-based and auto-induction approaches in a shake flask scale and the yield of GM-CSF expression and biomass production was identified. Results showed higher biomass production and expression yield for GM-CSF in case of auto-induction comparing with IPTG-induction. The auto-induction approach was also performed in a fed batch fermentation process in a 2-L bioreactor scale. The feeding strategy yielded an amount of 300 mg/L GM-CSF within 20 h of induction. However, most of the over-expressed GM-CSF was produced as inclusion bodies and following purification and refolding, a final yield of 90 mg/L was achieved. These results suggest that auto-induction approach can be effectively applied in fed-batch fermentation for the large scale production of GM-CSF; however, further optimization of purification process is obligatory to increase the purification yield.

Pulmonary alveolar proteinosis (PAP) is a diffuse pulmonary disease characterized by the intra-alveolar accumulation of formless, proteinaceous material. Lipids and proteins materials with specific staining appearance in the alveoli impair pulmonary gas transfer in PAP. The severity of this condition ranges from an asymptomatic clinical presentation to respiratory failure and death. PAP is an extremely rare disorder, occurring worldwide with an estimated prevalence of 0.1 per 100000 individuals. Although the pathogenesis of PAP has remained unknown, most investigators have considered this condition to be caused by the impaired clearance of lipids and surfactant proteins from the airspaces. These functions are known to be performed by alveolar macrophages and type 2 epithelial cells. It is likely that granulocyte macrophage-colony stimulating factor (GM-CSF) dysfunction on macrophages is responsible for PAP. Primarily, in most adult patients with PAP, antibodies against GM-CSF have been observed with dysfunction of macrophages. Secondly, alveolar macrophage dysfunction plays a role in the impaired secretion of surfactant in this disease. It has been noted that both impaired secretion of surfactant and impaired phagocytosis are responsible for disease pathogenesis.
Case Report: A 40-year-old man who had suffered from a cough with sputum for more than 2 years, with no associated fever, referred to our clinic. He had been diagnosed with pneumonia and treated unsuccessfully with antibiotics. His past medical history showed that he had a chronic history of a cough, easy fatigability and shortness of breath upon mild exertion. Computed tomography (CT) imaging of the chest revealed bilateral diffuse reticulonodular opacities and a crazy-paving pattern, which was suggestive of alveolar proteinosis.
PAP is a generalized pulmonary disorder caused by the collection of formless, proteinaceous material with specific staining appearance in the alveolus.

The cytokine of granulocyte macrophage colony stimulating factor (GM-CSF) is aglycoprotein, which is synthesized in the female reproductive tract and has embryonic trophiceffect in mammals. The objective of this study was to examine the optimal dosage of GMCSFto improve the mouse embryo development in vitro. To collect two and eight cellsembryos, the pregnant NMRI mice were sacrificed by cervical dislocation at 48 h and 72 hpost hCG injections, respectively. The embryos were cultured randomlly in T6 mediumsupplemented with 5 mg /ml bovine serum albumin (BSA) and 0, 2, and 10 ng / ml humanrGM-CSF. The data of blastocyst formation and hatching in different groups of embryoculture were compared by chi-square analysis. The results showed that the developmentalrates of 2 and 8 cells embryos to hatching blastocyst in the presence of 2 ng/ml of GM-CSFtheir control groups (51.5% and 49.7%, respectively) were more than those in the othergroups, but insignificant. It seems more researches are necessary to confirm this suggestionthat the GM-CSF with 2 ng/ml concentration may have a better potential, not only to enhancethe developmental rates of 2 and 8 cells embryos but also for decreasing the degeneration ofthose embryos.