Immunological memory as the fundamentals of vaccines Immunological memory and vaccines

The immune system also called as the defense system involves many different cells that work as soldiers in an individual. These immune cells provide protection against various pathogens. For better protection of an individual the immune systems has the ability to memorize or remember the pathogen. This ability is known as immunological memory. With the help of immunological memory the immune memory cells remember the antigen and are prepared if there is an encounter with the antigen in future. The immunological memory can be developed against certain strains with the help of different types of vaccines. Such types of vaccines that are currently being used to save lives are, Live attenuated vaccines, Toxoid vaccines, Subunit vaccines, Glyco-conjugated vaccines, and Killed/Inactivated vaccines. These vaccine show different efficiency. Hence, the immunological memory generated after a single vaccination may wear off with time. Multiple numbers of shots are required for the development of long term memory. All these types of vaccines vary from each other in their manufacturing and also in their mechanism of providing long term immunological memory. They show many pros and cons but their advantages are greater than their disadvantages. Thus, are preferred to be used for the betterment of mankind.   

Species Diversity and Biological Activities of Some Lichens of District Mansehra

The present study was designed to explore the biodiversity of lichen species in District Mansehra, Khyber Pakhtunkhwa, and hunt potential extracts with high biological activities. For this purpose, species diversity of lichens in the study area was explored from January 2012 to July 2015. The study recorded 110 lichen species distributed within 27 families and 56 genera from research area. Twelve novel lichens species were also identified as new to Pakistan including Acarospora veronensis A. Massal., Anaptychia crinalis (Schleich.) Vezda, Candelariella efflorescens R.C. Harris & W.R. Buck, Cladonia caespiticia (Pers.) Flörke, Cladonia floerkeana (Fr.) Flörke, Lecanora chlarotera Nyl., Lecanora pulicaris (Pers.) Ach., Lepraria elobata Tønsberg, Nephroma parile (Ach.) Ach., Punctelia subrudecta (Nyl.) Krog, Rhizocarpon lecanorinum Anders and Trapeliopsis granulosa (Hoffm.) Lumbsch. Additionally, another remarkable milestone was the identification of 59 lichen species belonging to 17 families and 35 genera for the first time in District Mansehra, Khyber Paktoonkhawa. Most abundant were crustose lichens consisting of 51 species (46.36%) while foliose lichens comprised 11 species (42.72%). On the basis of hosted substrate, 43 species (39.09%) were found on bark followed by 42 species (38.18%) on rocks and 12 species (10.9%) on soil. The distribution percentage of lichen species in various habitats showed that 55 lichen species (50%) were Corticolous followed by saxicolous with 42 species (38.18%), tericolous with 12 species (10.9%) and muscicolous having only one species (0.9%). The leading lichen family was Parmeliaceae with 12 genera (10.90%) followed by Physciacea with 7 genera (6%), Teloschistaceae and Verrucariaceae with 4 genera (3.63%) each. In present study, among the 110 identified lichens species, 63 lichen species (57.27%) were macro-lichens while remaining 47 species (42.72%) were micro-lichens. For biological assays, antibacterial potential of crude acetonic and methanolic extracts of ten lichen species was assessed against Gram+ve and Gram-ve bacteria. The maximum zone of inhibition (12.66 mm) for acetone extracts were shown by Flavoparmelia caperata, Lecanora allophana and Cladonia pyxidata against Escherichia coli (ATCC_39111), Enterococcus faecalis (ATCC-19433) and Staphylococcus aureus (ATCC_33591). However, crude methanol extracts exhibited a slightly lower action of lichen species Flavoparmelia caperata and Rhizocarpon viridiatrum (inhibition= 12.33 mm) against E. coli. Similarly, the maximum antifungal activity for crude acetone extracts of ten lichen species were shown by Caloplaca decipine and Flavoparmelia caperata (11.66 mm) against Aspergillus niger (ATCC_16888) and A. fumigatus (ATCC_16424) while for methanol extract, maximum activity were shown by Flavoparmelia caperata and Lecanora allophana (10.66 mm) against A. fumigatus and A. niger. Cytotoxicity of crude acetone and methanol extracts of the tested lichen species were evaluated by Brine Shrimp lethality assay. The maximum cytotoxic effect of crude acetone extract was recorded for Flavopunctelia flaventior (60%) while maximum cytotoxic effect in crude methanol extract was shown by Flavoparmelia caperata (53%). Antitumor activity of crude aetone and methanol extracts of ten selected lichen species were determined by potato disc bioassay. The highest tumor inhibition in crude acetone extract was shown by Flavoparmelia caperata (40%) while in crude methanolic extracts maximum tumor inhibition was shown by Flavopunctelia flaventior (38%). The highest free radical scavenging activity for crude acetone extract was manifested by Cladonia pyxidata (66%) while in crude methanol extract; maximum activity was shown by Rhizocarpon viridiatrum (57%). The present research will be helpful in the documentation of lichen flora of District Mansehra.It is expected that the present work on diversity and biological activities of lichens of District Mansehra will be helpful not only for identification of lichen species but also in opening up Pakistan unique lichen flora for further study.