Late immunity

Egg-induced immunity appears to involve stage-specific immunogens against (a) the tissue phase of egg challenge (early response) and (b) the lumen phase of cysticercoid challenge (late response). This immunogenetic pattern is thus similar to the development of early and late immunity in larval taeniid cestodes (Fig. 11.7). The effector mechanism of the early response has been shown to be thymus dependent, X-irradiation sensitive, cell mediated and antibody mediated the response is visualised by eosinophilia infiltration around the invading oncospheres (Fig. 11.6) (353). 

Fig. 11.7. Pattern of immune responses of an oncosphere of a taeniid cestode (e.g. Echinococcus granulosus) during initial penetration of the hatched oncosphere (initiating early immunity ) and its subsequent migration to, and establishment in, its definitive site, where it is subject to late immunity . The exact site of hatching (in man) is unknown most eggs probably hatch in the upper duodenum.

A broad and vigorons T cell response generally accompanies elimination of HBV as well as HCV infection. By contrast, patients with chronic hepatitis B or C tend to have late, transient, or narrow T cell responses. In a long-term follow-up of HBV-infected patients receiving HPC transplants from HBV-immune individuals, 20 of 31 recipients cleared their HBV infection (Hui et al. 2005). In principle, these results encourage the development of adoptive T cell transfer strategies for the treatment of chronic viral hepatitis. However, it is still controversial whether induction of an efficient T cell response is the cause or the consequence of viral clearance. Furthermore, T cell responses do not only contribute to virus control but also to disease pathology (Rehermann and Nascimbeni 2005). 

Iwamura and Ueda [386] described compound (611) as a CB2 selective inverse agonist in a patent application. The potential therapeutic roles of CB2 antagonists are not clearly defined at the moment, although roles in regulation of the immune system and inflammation have been widely proposed. This patent application describes that activity of compound (611) in a mouse model of asthma, in which the compound suppressed immediate and late-phase asthmatic response and airway hyper-responsiveness. 

The drawback with late lambing is its dependence either on a buoyant store lamb market in September and October or else on the feasibility of growing a catch crop, such as stubble turnips or rape, on the farm, so that lambs can be fattened satisfactorily outdoors during the autumn and early winter. Again, intestinal parasites can be a problem, with the period of maximum risk, late July and August, occurring before the younger lambs have had a chance to build up their own immunity. 

Catch-up Immunization Schedule for Persons Aged 4 Months-18 Years Who Start Late or Who Are More Than 1 Month Behind - UNITED STATES 2007... 

At least two specific properties make the immune system vulnerable to chemical or physical insults (1) the immune system develops rather late in life (thymus development lasts at least until puberty), and some bone marrow-dependent immune components are continuously renewed (i.e., granulocytes), and (2) each pathogen attack, as well as immune surveillance, demands a delicate control of the balance between activation, silencing, and regulation of immune reactivity. 

In the late 1700s, Jenner heard that people who worked with cattle and had caught the cowpox disease (a mild disease related to smallpox) were immune and never caught smallpox. In 1796, he proceeded to inoculate a boy using the fluid from the blister of a woman with cowpox. The boy developed cowpox. Two months later, Jenner inoculated the boy with fluids from the blister of a smallpox sufferer. The boy became immune and did not get smallpox. 

These experiments also make another important point, namely that it is apparently never too late to interfere with an immune response by Treg suppression since the experiments show that suppression can affect fully differentiated effector cells. This is good news in the sense that the obviously effective suppression late during an immune response can revert rather than prevent unwanted immunity, a concept that may become extremely useful in the clinic. 

---