Research by Nam Dang related to the effect of papaya leaf on the immune system may have advice for our ebola crisis. Best of all, papaya leaf is indigenous to these affected African countries and their ethno medicine includes the use of papaya leaf tea.
Follows is an article from 2003 that describes the effect of Ebola on DC cells and also the correlation to diseases such as Dengue H fever (which papaya leaf tea has shown effect). Then the leading research by Nam Dang and others which discusses the effect of carica papaya leaf tea extract and its related effect on the immune system.
Am J Pathol. Dec 2003; 163(6): 2347–2370.
Pathogenesis of Ebola Hemorrhagic Fever in Cynomolgus Macaques
Evidence that Dendritic Cells Are Early and Sustained Targets of Infection
Thomas W. Geisbert,* Lisa E. Hensley,* Tom Larsen,* Howard A. Young,† Douglas S. Reed,* Joan B. Geisbert,* Dana P. Scott,* Elliott Kagan,‡ Peter B. Jahrling,* and Kelly J. Davis*
“…While the importance of monocytes/macrophages in EBOV pathogenesis have been well-documented, 28,30,41,43-44 few studies have addressed the importance of DC in EBOV pathogenesis; these cells also play important roles in initiation and regulation of the host immune response. DC are a family of professional antigen-presenting cells, derived from bone marrow, which have the ability to initiate and modulate cell-mediated immune responses. 45,46 Immature DC function as sentinels of the adaptive immune system; they are located in the peripheral tissues where they capture and process exogenous antigens and migrate to regional lymph nodes where they undergo maturation. A wide variety of stimuli, including infectious virus, bacterial antigens, or inflammatory cytokines, can trigger maturation of DC, which is characterized by phenotypic changes, including up-regulation of MHC and costimulatory molecules, and production of IL-12. Presentation of acquired antigen by mature DC leads to T-cell activation. 47,48 Monocytes circulating in the blood could be equally important in the DC response as circulating monocytes counter infection by crossing the endothelial barrier, infiltrating the focus of infection, and developing either into macrophages or DC.
Regarding the importance of EBOV predilection for DC in disease pathogenesis, we speculate that EBOV acts in a manner similar to other viruses that are known to disable the host immune response by attacking and manipulating the very cells that play the most critical roles in initiating the antiviral immune response. DC-tropic viruses such as HIV, 49,50 measles virus, 51-53 LCMV, 54 Dengue, 55 cytomegalovirus, 56 and HSV1 57 have evolved mechanisms to impair the function of DC, thereby enhancing their chance to escape immune surveillance…”
“…The current study demonstrates, for the first time, that DC are early and sustained cellular targets of EBOV in nonhuman primates; that lymphocyte apoptosis is a relatively early event in disease progression, and furthermore, it is the NK cell fraction that is likely lost through increased apoptosis early in the course of infection.”
“…While the importance of monocytes/macrophages in EBOV pathogenesis have been well-documented, 28,30,41,43-44 few studies have addressed the importance of DC in EBOV pathogenesis; these cells also play important roles in initiation and regulation of the host immune response. DC are a family of professional antigen-presenting cells, derived from bone marrow, which have the ability to initiate and modulate cell-mediated immune responses.”
Journal of Ethnopharmacology
journal homepage: http://www.elsevier.com/locate/jethpharm
Aqueous extract of Carica papaya leaves exhibits anti-tumor activity and immunomodulatory effects
Noriko Otsukia,1, Nam H. Dangb,1, Emi Kumagaia, Akira Kondoc, Satoshi Iwataa, Chikao Morimotoa,d,∗
a Division of Clinical Immunology, Advanced Clinical Research Center, The Institute of Medical Science, The University of Tokyo, Japan b Division of Hematology/Oncology, The University of Florida, Gainesville, FL, USA
c Kondo Hospital, 1-6-25, Nishishinhama, Tokushima, Tokushima 770-8008, Japan
d Department of Rheumatology and Allergy, Research Hospital, The Institute of Medical Science, The University of Tokyo, Japan
“It is known that p40, a subunit of IL-12p70, is produced by antigen-presenting cells (APCs), such as monocytes or dendritic cells (DCs). It has also been shown that human IL-12p70 production from DCs is dependent on CD40-40L interactions, whereas p40 pro- duction is not (Cella et al., 1996). Based on these previous reports, it is conceivable that CP extract may modify not only activation of APCs, but also the interaction of T-APCs or T-B cells; namely, CP extract modifies both innate and acquired immunity.”
“…The family of monocyte-chemoattractant proteins, including CCL2 (MCP-1), CCL7 (MCP-3) and CCL8 (MCP-2), are considered to play important roles in the recruitment of monocytes, basophils, plasmacytoid dendritic cells and memory T lymphocytes to sites of inflammation. Their enhanced expression is correlated with vari- ous cytokines, such as IL-1, TNF- and IFN- (Viola and Luster, 2008). In addition, patients with high circulating level of CCL2 had significantly higher survival rate than those with low CCL2 pro- duction (Monti et al., 2003)…”
“…Our studies suggest that in addition to its anti- tumor effect, the fact that CP extract enhances production of Th1 type cytokines, such as IL-12, IFN- and TNF-, raises the possibility that CP extract may contribute to the treatment of Th2-mediated allergic disorders, such as allergic rhinitis and bronchial asthma, or as an adjuvant of various vaccines by inducing a shift from Th2 to Th1 type immune response.”
“…Conclusion: Since Carica papaya leaf extract can mediate a Th1 type shift in human immune system, our results suggest that the CP leaf extract may potentially provide the means for the treatment and prevention of selected human diseases such as cancer, various allergic disorders, and may also serve as immunoadjuvant for vaccine therapy.”