Apresentação em tema: "Porque não temos vacinas contra parasitas? Manoel Barral-Netto FIOCRUZ-Bahia e FAMEB-UFBA."— Transcrição da apresentação:
Porque não temos vacinas contra parasitas? Manoel Barral-Netto FIOCRUZ-Bahia e FAMEB-UFBA
2 Porque não temos vacinas contra parasitas? O sucesso das vacinas –Anticorpos neutralizantes O insucesso das vacinas –Complexidade da RI adquirida além dos Ac; –Sistema Imune Inato; –Outros fatores que interferem na RI. Perspectivas O insucesso das vacinas e a evolução. 2
A era de Jenner As early as the 10th century AD, fluid from smallpox lesions or dried scabs from healing sores given to susceptible individuals to make them immune variolation India and China Variolation resulted in less severe disease than natural infection nasty lesion at the inoculation site, blisters, mild rash, fever, myalgia, and lethargy, but mortality appeared to have been only 1% to 2%, and generalized scarring was also rare. Variolation worked, but the disadvantages were such that the medical profession as a whole remained skeptical.
The resemblance which the pustule thus excited on the boy's arm bore to variolous inoculation, yet as the indisposition was barely perceptible, I could scarcely persuade myself the patient was secure from the smallpox. However, on his being inoculated some months afterwards, it proved that he was secure. A further variolation five years later confirmed the maintenance of immunity. The resemblance which the pustule thus excited on the boy's arm bore to variolous inoculation, yet as the indisposition was barely perceptible, I could scarcely persuade myself the patient was secure from the smallpox. However, on his being inoculated some months afterwards, it proved that he was secure. A further variolation five years later confirmed the maintenance of immunity. Jenner's paper was rejected by the Transactions of The Royal Society, so he published his Inquiry privately. 1796
O nascimento da imunologia (1875- 1910) Pasteur : Pasteurella septica (cholera) attenuated in vitro, injection of attenuated bacteria protected chickens from the effects of virulent cultures (VACCINE). Koch: cholera vibrio, killed whole-cell bacteria vaccine. All that was needed: isolate the causative agent, establish Koch's postulates, attenuate or kill the agent, and immunize. Controversy Early preparations were neither as safe nor as protective as claimed, production facilities, regulatory agencies not well developed + design of clinical trials left much to be desired. Significant professional reservations about vaccines and educated parents not convinced about the advantages of immunization as a whole.
Primeira vacinas contra bactérias (1910-1930) Koch's isolation of the tubercule bacillus, the search for a tuberculosis (TB) vaccine began. Calmette and Guerin started with an isolate of TB from a cow 213 subcultures (13 years) tried the culture orally in a newborn infant BCG. Given intradermally effective in infants for the prevention of miliary TB and tuberculous meningitis. World War I - opportunity for the whole cell–killed bacterial vaccines (typhoid), systematic use x absence of a formal clinical trial. Bordetella pertussis 1923 formalin treatment of diphtheria toxin could render it harmless, preserving its immunogenic potential toxoids progressive introduction into industrialized countries (1930) lowered the impact of both diphtheria and tetanus.
Primeiras vacinas contra vírus: 1930-1950 1930s was a heady period for isolation of disease-causing viruses, but tissue culture was still the realm of a few practitioners. Goodpasture + Burnet improvement of techniques for growing viruses and Rickettsiae in embryonated hen's eggs. Theiler: safe and effective live attenuated yellow fever vaccine, 17D and first-generation killed whole virus influenza vaccines and vaccines against typhus important for troops in World War II. Formalin-killed mouse brain–derived Japanese B encephalitis vaccine was also effective.
Revolução da cultura de células 1950-1970 1955 - Salk's formalin-treated whole virus vaccine provided protection 1955 to 1961, 300 million doses administered, polio declined dramatically. Cutter Incident - faulty production techniques two lots of vaccine with inadequate formalin inactivation = 149 cases of polio. Development of live attenuated oral poliomyelitis vaccine of Sabin, first introduced in 1961 By 1965, had essentially replaced the Salk vaccine. Orally active, more convenient to use, and containing far fewer virions, much cheaper Very rare reversions to neurovirulence, estimated at one case per 2.7 million doses of oral poliomyelitis vaccine administered). Now – tetravalent vaccine available (measles – mumps – rubella - varicella)
Era molecular: 1970-1990 Surface antigen of the hepatitis B virus (HBsAg) = a single protein as a vaccine first vaccine manufactured through recombinant DNA technology. 350 million carriers of hepatitis B worldwide, 20% to 25% of carriers develop chronic liver disease, and a substantial proportion of these go on to primary hepatocellular carcinoma hepatitis B vaccine is the first anticancer vaccine in history. The great success of the hepatitis B vaccine new era in genetic engineering approaches. Subunit capsular polysaccharide vaccines against Streptococcus pneumoniae, Neisseria meningitidis, and Hemophilus influenzae B (Hib) licensed in the 1970s and early 1980s conjugation of the carbohydrate antigens to a protein carrier, usually diphtheria or tetanus toxoid effective T cell help and immunologic memory to develop.
Polio Eradication Progress, 1988 - 2002 Certified Polio-free regions (113 countries) Endemic with wild polio virus ( 7 countries) Source: WHO AFP surveillance database data from 192 WHO member states Not Certified but non-endemic (72 countries) Slide Date: October 03
13 Esquema vacinação 0-6a, US 2007 The Jordan Report, NIAID 2007
14 Esquema vacinação 7-18a, US 2007 The Jordan Report, NIAID 2007
15 Esquema vacinação adultos, US 2007 The Jordan Report, NIAID 2007
16 Vacinas disponíveis Tipo de vacina VírusBactériasOrganismomorto Polio, sarampo, caxumba, rubéola, varicela, febre amarela Tuberculose, febre tifóide Organismo atenuado Polio, influenza, raiva, Hepatite A Pertussis, febre tifóide, cólera Subunidades Hepatite B H. influenza B, pertussis, menigococos, pneumococos, febre tifóide
19 O insucesso das vacinas Complexidade da RI adquirida para além dos Acs Linfócitos T CD8+; Sistemas de citocinas e quimiocinas; Linfócitos T multifuncionais; Memória dos linfócitos T; Sinais inibitórios. 19
Imunogenicidade: PAMPs x PRRs (TLRs, similares a IL-1bR)
Plasticidade funcional de DCs: Estimulação de diferentes PRRs pode estimular respostas adaptativas distintas. TLR Pulendram & Ahmed, 2006
Imunogenicidade: outros PRRs MBL – reconhecimento de carboidratos, atua como opsonina, capaz de ativar a cascata do complemento. DC-SIGN – presente na superfície, reconhecimento de carboidratos Danger signal – sinal de estresse/injúria ou patógeno liberação de proteínas do hospedeiro potentes imunoestimuladores –(alarmins – defensins e cathelicidins possuem atividade antimicrobiana E agem como imunoestimulantes).
PRR, TLR agonists Ag carriers Immunostimulation Potential toxicity Liposomes Polymeric particles Mineral salts, alum Emulsion s ISCOMS, virosomes, virus-like particles 2 3 7 9 4 PAMP AND AG PARTICULATE CODELIVERY: THE PERFECT MIX THREE COMPONENT VACCINE MODEL AG + PAMP
ADJUVANT A TCR CD28B7 MHC II APC Th cell Signal O Signal 1 Signal 2 ADJUVANT B ADJUVANT C PAMPs Polymeric particles Liposomes Emulsions (MF59) Mineral salts: Alum Cytokines CD40L AG + adjuvant Protein, peptides, DNA, RNA Any substance or strategy that augments the immune response against an Ag
It is now possible to select those antigens that show limited or absent antigenic variability and antibody-mediated protection. This approach to vaccine discovery starts with the analysis of the information in silico reverse vaccinology
51 É possível obter as novas vacinas? O insucesso das vacinas e a preservação da espécie. Sucesso contra enfermidades que matam antes da idade reprodutiva.
Figure 1 Role of maternal serum and milk antibodies (Ab) in protecting offspring. (A)Maternal antibodies transferred (via placenta) protect offspring and attenuate systemic infections during the first 6–12 months after birth. Early (i) or late (ii) weaning influences attenuation of gastrointestinal infection. (i) Western countries (ii) developing countries (B) If there are no specific antibodies in maternal serum this protection is absent. In partsA and B, note that the offsprings antibodies start to be produced slowly within the first weeks after birth but provide effective protection only at 3–6 months of age; during this time active vaccination will enhance generation of specific antibodies by offspring. Zinkernagel 2003
53 É possível obter as novas vacinas? Vacina contra-infecção vs Vacina contra-doença