Emerging aspects of leukocyte migration

Wild epiphytic Bangladeshi orchids Cymbidium aloifolium (L.) Sw. and Papilionanthe teres (Roxb.) Lindl. potentially modulates the immune functions in Swiss albino mice

Objective

This research investigated the immunomodulatory potentials of two medicinally important wild epiphytic Bangladeshi orchids Cymbidium aloifolium and Papilionanthe teres using Swiss albino mice.

Materials and Methods

Orchid extracts were prepared using a cold methanol extraction procedure. To assess the immunomodulatory action, Swiss albino mice of either sex weighing 25-35 gm were divided into five groups each with six animals. Sheep red blood cells (SRBC) of 0.5 × 10⁹ cells/ml were used to immunize all mice on the 7th day, and a booster dose of the same quantity of SRBC was given on the 11th day of the experiment. After 14 days of oral treatment with 100 and 200 mg/kg bw of orchid extract, the mice were sacrificed to collect serum and organs. Hematological assays, delayed type of hypersensitivity assays, phagocytic index (PI), and histopathological investigations were used to assess in vivo immunomodulatory efficacy.

Results

The body weight changes of the experimental animals were considerably greater at 100 mg/kg bw than at a higher dose (200 mg/kg bw). There was a substantial improvement of relative organ weights of the thymus and spleen at the low dose, but no effect on kidney weights was evident. The liver weight increased significantly (p < 0.05) at both doses. Total neutrophil, leukocyte, and lymphocyte counts, hemoglobin percentage, delayed hypersensitivity reaction, and PI were all significantly (p < 0.05) increased in mice receiving the lower dose. In contrast to the control group, the higher dose reduced immunological response, suggesting the negative influence of a higher dose of extracts on the immune reaction.

Conclusions

The results demonstrate that orchid extracts can potentially modulate the innate immune system in the experimental animal.

Immunomodulatory Activity of Momordica charantia L. (Cucurbitaceae) Leaf Diethyl Ether and Methanol Extracts on Salmonella typhi-Infected Mice and LPS-Induced Phagocytic Activities of Macrophages and Neutrophils

Infections due to Salmonella strains constitute one of the major health problems in humans, particularly in Africa. The use of traditional herbs has proven effective in reducing the incidence of infection in some high-risk groups. To assess the effects of Momordica charantia leaf extracts that influence blood infection, an in vitro study of the effect on macrophages and neutrophils and treatment of mouse model of S. typhi infection was done. Methanol and diethyl ether extracts were concerned by this study. In vitro study was to assess the effects of extracts on phagocytosis, and related intracellular killing mechanisms of macrophages were examined. Later, mobilization of leukocytes and production of antibodies against S. typhi were measured followed by quantitating cultures evaluation of the blood infection of orally inoculated mice with S. typhi. Ingestion or attachment of carbon particles, production of superoxide anion, nitric oxide, and that of lysosomal acid phosphatase by macrophages and neutrophils were significantly increased by methanol and diethyl extracts at concentrations ranging from 40 μg/ml to 640 μg/ml. Antibody titer and mobilization of leukocytes, particularly lymphocytes against S. typhi, were highly increased by both methanol and diethyl extracts at concentrations of 500 and 1000 mg/kg. At the same time, the extracts have reduced the rate of blood colonization in mice inoculated with 10⁸ CFU of S. typhi for 28 days. Reduction in blood colonization or infection rates was similar for the levamisole mice group. The results of this study should prove that the leaves of Momordica charantia are useful for the treatment of infections by Salmonella strains and for the assessment of drugs for therapeutic intervention.

Immunomodulatory activity of Buchholzia coriacea seed methanol extract on Trypanosoma brucei brucei infected mice

CONTEXT

The seeds of Buchholzia coriacea Engler (Capparaceae) are used in Eastern Nigeria to treat feverish conditions, and to treat malaria and sleeping sickness that cause fever.

OBJECTIVE

The current study assesses the immunomodulatory activity of Buchholzia coriacea seed extract on Trypanosoma brucei brucei infected mice.

MATERIALS AND METHODS

Delayed hypersensitivity reaction, humoral antibody response and in-vivo leucocyte mobilization tests were assessed in three different experiments to determine the effect of the extract on immune response. Seventy-five (75) mice (25 mice per experiment) were used for the study and were each infected with 1.00 × 10⁶ trypanosomes intra-peritoneally. Groups A, B and C were given 250, 500 and 1000 mg/kg of the extract, respectively, group D received 7.5 mg/kg body weight of levamisole and group E was the control. Sheep RBCs were used as antigen.

RESULTS

The acute toxicity tests did not cause clinical signs or death within 24 h post treatment at all the doses tested. The extract inhibited delayed hypersensitivity reaction by 20.9 and 20.8% at 250 and 500 mg/kg, respectively, while at 1000 mg/kg, the paw size increased (-101.9%) when compared with the control. The extract elevated the antibody titre from 1.60 ± 0.40 for control to 8.00 ± 3.58 for 500 mg/kg group. The extract increased in total leucocytes counts.

DISCUSSION AND CONCLUSION

The extract has a very wide safety margin and was able to improve immune response. The results of the present study showed that Buchholzia coriacea seed methanol extract possesses immunostimulatory activity on trypanosome-infected mice.

A dual-docking microfluidic cell migration assay (D2-Chip) for testing neutrophil chemotaxis and the memory effect

Chemotaxis is a classic mechanism for guiding cell migration and an important topic in both fundamental cell biology and health sciences. Neutrophils are a widely used model to study eukaryotic cell migration and neutrophil chemotaxis itself can lead to protective or harmful immune actions to the body. While much has been learnt from past research about how neutrophils effectively navigate through a chemoattractant gradient, many interesting questions remain unclear. For example, while it is tempting to model neutrophil chemotaxis using the well-established biased random walk theory, the experimental proof was challenged by the cell's highly persistent migrating nature. A special experimental design is required to test the key predictions from the random walk model. Another question that has interested the cell migration community for decades concerns the existence of chemotactic memory and its underlying mechanism. Although chemotactic memory has been suggested in various studies, a clear quantitative experimental demonstration will improve our understanding of the migratory memory effect. Motivated by these questions, we developed a microfluidic cell migration assay (so-called dual-docking chip or D2-Chip) that can test both the biased random walk model and the memory effect for neutrophil chemotaxis on a single chip enabled by multi-region gradient generation and dual-region cell alignment. Our results provide experimental support for the biased random walk model and chemotactic memory for neutrophil chemotaxis. Quantitative data analyses provide new insights into neutrophil chemotaxis and memory by making connections to entropic disorder, cell morphology and oscillating migratory response.

CRAM-A indicates IFN-γ-associated inflammatory response in breast cancer

Atypical chemokine receptors (ACKRs) function as endpoint regulators of chemokine gradients. These non-signaling receptors that are transiently expressed under inflammatory conditions have critical roles in the control or maintenance of immune responses. Alternatively, here, CCRL2 (ACKR5) expression was determined to be constitutive in breast cancer cells. Increased amount of CCRL2 was also found in breast tumor tissues with high immune infiltration. Its expression was upregulated in the presence of pro-inflammatory cytokines, IL-1β, TNF-α, IL-6, and especially IFN-γ⋅ Moreover, an alternative transcript of CCRL2 gene, CRAM-A, was specifically expressed in a transient fashion under the influence of IFN-γ. CRAM-A expression was also positively correlated with the presence of IFN-γ mRNA in patient samples. CCRL2-associated chemotactic molecules, chemerin, CCL19 and CCL5, were also detected in cancer tissues and CCL5 mRNA level was correlated with that of CRAM-A and IFN-γ. Hence, in breast cancer, CRAM-A becomes specifically upregulated under inflammatory stimuli and may serve as a potential marker of immune response.