Drug – bio-affecting and body treating compositions – Antigen – epitope – or other immunospecific immunoeffector – Bacterium or component thereof or substance produced by said...
Reexamination Certificate
2000-07-27
2003-07-01
Graser, Jennifer E. (Department: 1645)
Drug, bio-affecting and body treating compositions
Antigen, epitope, or other immunospecific immunoeffector
Bacterium or component thereof or substance produced by said...
C424S234100, C424S253100, C424S255100, C424S256100, C424S204100, C424S197110, C424S196110, C424S201100, C424S203100, C424S274100
Reexamination Certificate
active
06585981
ABSTRACT:
BACKGROUND OF THE INVENTION
Porcine respiratory disease complex (PRDC) is an increasingly important cause of lowered swine productivity as characterized by slow growth, decreased feed efficiency, anorexia, fever, cough, and dyspnea.
Mycoplasma hyopneumoniae
, also called
Mycoplasma suipneumoniae
, is the causative agent of swine mycoplasmal pneumonia (also known as enzootic pneumonia, virus pneumonia, infectious pneumonia, and anterior lobe pneumonia of pigs).
M. hyopneumoniae
is a small, prokaroytic microbe smaller and simpler in structure than bacteria, but more complex than viruses. Unlike viruses, they are capable of a free living existence, through they are often found in association with eukaroytic cells as they have absolute requirements for exogenous sterols and fatty acids which generally necessitates growth in serum-containing media.
M. hyopneumoniae
is bound by a cell membrane but not by a cell wall. They have an extremely small genome, approximately 750,000 base pairs in length. The pig is the only known host of this mycoplasma.
Mycoplasmal pneumonia is one of the most prevalent swine respiratory tract diseases among the pig-raising countries of the world. Surveillance data from PigMon, a monitoring program that evaluates lesions in farms throughout the upper Midwest of the United States, identified pneumonia in 97% of the Midwestern swine herds, with >70% prevalence among the sampled animals (Dybvig 1992). Mycoplasmal pneumonia has a low mortality rate but a high morbidity rate (30-80%). The disease generally results in considerable economic loss, because it causes a depression in growth rate, inefficiency and sickness in animals.
The disease is transmitted from pig to pig through the nasal passages by airborne organisms expelled from infected pigs. The mycoplasma establish themselves deep in the apical and cardiac lobes of the lungs where they cause visible plum colored or gray lesions and cause difficulty in breathing and reduced weight gain. The primary infection by
M. hyopneumoniae
may be followed by secondary infection by other mycoplasma species (e.g.,
M. hyorhinus
and
M. floculare
) as well as bacterial pathogens (Pasteurella and Bordetella species). These respiratory tract diseases caused by
M. hyopneumoniae
cause decreased weight gain at a time when animals are being fed for market. Thus, animals which have been infected with this organism will be worth less at slaughter than their non-infected counterparts.
Even though many farms have adopted multiple-site, high health programs, the prevalence of pneumonia has not declined markedly but may be changing in epidemiology. Due to the serious economic consequences of pig pneumonia, vaccines against, and treatments for
Mycoplasma hyopneumoniae
have been sought. Mycoplasma prevention in pigs is accomplished by a mixture of antibiotic treatment and vaccination. This approach has the drawback of being both expensive and unpredictable, with many farms showing little improvement following these procedures. Vaccination against
Mycoplasma hyopneumoniae
is a relatively recent introduction, with vaccines being available commercially only for the last 6-7 years.
Although Mycoplasma vaccines for pigs have been a huge commercial success, their merits under field conditions are still very much under debate. In general, these vaccines reduce average lesion scores of pneumonic lungs at slaughter, but do not impact the prevalence of affected pigs. That is, the same number of pigs are affected, but terminal lesions appear to be smaller. The impact of Mycoplasma vaccination on performance is even more suspect, with few, if any, papers showing a definite improvement in either gain or conversion.
The reason for the relatively unsatisfactory performance of these vaccines may be related to the fact that they are killed bacterins, together with the peculiarities of Mycoplasma infection in pigs.
M. hyopneumoniae
is a non-invading colonizer of ciliated epithelial cells. Because the organism does not invade the respiratory system, circulating antibodies elicited by the killed bacterins must cross the epithelial barrier and be secreted into the tracheobronchial lumen, a process that is difficult and ineffective. Mycoplasma bacterins must be able to elicit high levels of systemic antibodies, in order to be able to achieve this mucosal secretion. This, of course, requires relatively high doses of antigen and aggressive adjuvants, which makes these vaccines expensive and difficult to administer.
Another problem deals with the need to administer currently available vaccines by a double-dose injectable method. Such a double-dose method requires considerable pig handling, which is time-intensive and results in stress to the animals. As farms grow larger, double-dose, injection vaccination methods are becoming increasingly undesirable, with producers requiring an alternative vaccination method that does not require such handling.
Therefore, an ongoing need exists for a safe, effective vaccine against
M. hyopneumoniae
that is easy to administer.
SUMMARY OF THE INVENTION
The present invention provides an isolated and purified temperature-sensitive
Mycoplasma hyopneumoniae
bacterin. The bacterin may be ATCC deposit no. PTA-3549 (deposited in the American Type Culture Collection, 10801 University Blvd., Manassas, Va. 20110-2209, on Jul. 24, 2001).
The present invention also provides a vaccine preparation containing a live temperature-sensitive
Mycoplasma hyopneumoniae
bacterin in combination with a physiologically-acceptable, non-toxic vehicle. The bacterin may be ATCC deposit no. PTA-3549. The vaccine preparation may further contain an immunological adjuvant. Also, the vaccine preparation may contain at least one additional infectious agent. An infectious agent may be a virus, a bacterium, a fungus or a parasite. In particular, the infectious agent may be
Borderella bronchiseptica, Pasteurella multocida
types A or D, or
Haemophilus parasuis.
The present invention also provides a method of inducing an immune response and/or protecting a susceptible swine against colonization or infection of a
Mycoplasma hyopneumoniae
by administering to the swine an effective amount of a vaccine preparation containing a live temperature-sensitive
Mycoplasma hyopneumoniae
bacterin in combination with a physiologically-acceptable, non-toxic vehicle. The vaccine preparation may further contain an immunological adjuvant. The vaccine may be administered by subcutaneous or intramuscular injection, oral ingestion, or intranasally. The vaccine preparation may be administered in one or more doses.
DETAILED DESCRIPTION OF THE INVENTION
The term “vaccine” is defined herein in its broad sense to mean a biological agent used to produce active immunity. Vaccines generally employ one of four categories of antigens: live microorganisms administered via an unnatural route, live attenuated microorganisms, killed microorganisms and fractions or even a single antigen or product of a microorganism. In all situations, the goal is to present antigens without giving the disease. A number of different inactivating agents and means have been employed including formalin, azide, freeze-thaw, sonication, heat treatment, sudden pressure drop, detergent (especially non-ionic detergents), lysozyme, phenol, proteolytic enzymes and propiolactone. Examples of vaccines include those described in U.S. Pat. Nos. 4,894,332; 5,788,962; 5,338,543; and 5,968,525; and EP 571,648.
An immunological response to a composition or vaccine is the development in the host of a cellular and/or antibody-mediated immune response to the polypeptide or vaccine of interest. Usually, such a response consists of the subject producing antibodies, B cell, helper T cells, suppressor T cells, and/or cytotoxic T cells directed specifically to an antigen or antigens included in the composition or vaccine of interest. Vaccines of the present invention can also include effective amounts of immunological adjuvants, known to enhance an immune response.
Moreover, the goal of a vaccine is to provide
Graser Jennifer E.
Regents of the University of Minnesota
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